text: /* Copyright (c) 2001 Matej Pfajfar.
   * Copyright (c) 2001-2004, Roger Dingledine.
   * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   * Copyright (c) 2007-2019, The Tor Project, Inc. */
  /* See LICENSE for licensing information */
  
  /**
   * \file connection_edge.h
   * \brief Header file for connection_edge.c.
   **/
  
  #ifndef TOR_CONNECTION_EDGE_H
  #define TOR_CONNECTION_EDGE_H
  
  #include "lib/testsupport/testsupport.h"
  
  #include "feature/hs/hs_service.h"
  
  edge_connection_t *TO_EDGE_CONN(connection_t *);
  entry_connection_t *TO_ENTRY_CONN(connection_t *);
  entry_connection_t *EDGE_TO_ENTRY_CONN(edge_connection_t *);
  
  #define EXIT_CONN_STATE_MIN_ 1
  /** State for an exit connection: waiting for response from DNS farm. */
  #define EXIT_CONN_STATE_RESOLVING 1
  /** State for an exit connection: waiting for connect() to finish. */
  #define EXIT_CONN_STATE_CONNECTING 2
  /** State for an exit connection: open and ready to transmit data. */
  #define EXIT_CONN_STATE_OPEN 3
  /** State for an exit connection: waiting to be removed. */
  #define EXIT_CONN_STATE_RESOLVEFAILED 4
  #define EXIT_CONN_STATE_MAX_ 4
  
  /* The AP state values must be disjoint from the EXIT state values. */
  #define AP_CONN_STATE_MIN_ 5
  /** State for a SOCKS connection: waiting for SOCKS request. */
  #define AP_CONN_STATE_SOCKS_WAIT 5
  /** State for a SOCKS connection: got a y.onion URL; waiting to receive
   * rendezvous descriptor. */
  #define AP_CONN_STATE_RENDDESC_WAIT 6
  /** The controller will attach this connection to a circuit; it isn't our
   * job to do so. */
  #define AP_CONN_STATE_CONTROLLER_WAIT 7
  /** State for a SOCKS connection: waiting for a completed circuit. */
  #define AP_CONN_STATE_CIRCUIT_WAIT 8
  /** State for a SOCKS connection: sent BEGIN, waiting for CONNECTED. */
  #define AP_CONN_STATE_CONNECT_WAIT 9
  /** State for a SOCKS connection: sent RESOLVE, waiting for RESOLVED. */
  #define AP_CONN_STATE_RESOLVE_WAIT 10
  /** State for a SOCKS connection: ready to send and receive. */
  #define AP_CONN_STATE_OPEN 11
  /** State for a transparent natd connection: waiting for original
   * destination. */
  #define AP_CONN_STATE_NATD_WAIT 12
  /** State for an HTTP tunnel: waiting for an HTTP CONNECT command. */
  #define AP_CONN_STATE_HTTP_CONNECT_WAIT 13
  #define AP_CONN_STATE_MAX_ 13
  
  #define EXIT_PURPOSE_MIN_ 1
  /** This exit stream wants to do an ordinary connect. */
  #define EXIT_PURPOSE_CONNECT 1
  /** This exit stream wants to do a resolve (either normal or reverse). */
  #define EXIT_PURPOSE_RESOLVE 2
  #define EXIT_PURPOSE_MAX_ 2
  
  /** True iff the AP_CONN_STATE_* value <b>s</b> means that the corresponding
   * edge connection is not attached to any circuit. */
  #define AP_CONN_STATE_IS_UNATTACHED(s) \
    ((s) <= AP_CONN_STATE_CIRCUIT_WAIT || (s) == AP_CONN_STATE_NATD_WAIT)
  
  #define connection_mark_unattached_ap(conn, endreason)                  \
    connection_mark_unattached_ap_((conn), (endreason), __LINE__, SHORT_FILE__)
  
  /** Possible return values for parse_extended_hostname. */
  typedef enum hostname_type_t {
    BAD_HOSTNAME,
    EXIT_HOSTNAME,
    NORMAL_HOSTNAME,
    ONION_V2_HOSTNAME,
    ONION_V3_HOSTNAME,
  } hostname_type_t;
  
  MOCK_DECL(void,connection_mark_unattached_ap_,
            (entry_connection_t *conn, int endreason,
             int line, const char *file));
  int connection_edge_reached_eof(edge_connection_t *conn);
  int connection_edge_process_inbuf(edge_connection_t *conn,
                                    int package_partial);
  int connection_edge_destroy(circid_t circ_id, edge_connection_t *conn);
  int connection_edge_end(edge_connection_t *conn, uint8_t reason);
  int connection_edge_end_errno(edge_connection_t *conn);
  void connection_edge_end_close(edge_connection_t *conn, uint8_t reason);
  int connection_edge_flushed_some(edge_connection_t *conn);
  int connection_edge_finished_flushing(edge_connection_t *conn);
  int connection_edge_finished_connecting(edge_connection_t *conn);
  
  void connection_ap_about_to_close(entry_connection_t *edge_conn);
  void connection_exit_about_to_close(edge_connection_t *edge_conn);
  
  MOCK_DECL(int,
            connection_ap_handshake_send_begin,(entry_connection_t *ap_conn));
  int connection_ap_handshake_send_resolve(entry_connection_t *ap_conn);
  
  entry_connection_t  *connection_ap_make_link(connection_t *partner,
                                              char *address, uint16_t port,
                                              const char *digest,
                                              int session_group,
                                              int isolation_flags,
                                              int use_begindir, int want_onehop);
  void connection_ap_handshake_socks_reply(entry_connection_t *conn, char *reply,
                                           size_t replylen,
                                           int endreason);
  MOCK_DECL(void,connection_ap_handshake_socks_resolved,
            (entry_connection_t *conn,
             int answer_type,
             size_t answer_len,
             const uint8_t *answer,
             int ttl,
             time_t expires));
  void connection_ap_handshake_socks_resolved_addr(entry_connection_t *conn,
                                                   const tor_addr_t *answer,
                                                   int ttl,
                                                   time_t expires);
  
  int connection_exit_begin_conn(cell_t *cell, circuit_t *circ);
  int connection_exit_begin_resolve(cell_t *cell, or_circuit_t *circ);
  void connection_exit_connect(edge_connection_t *conn);
  int connection_edge_is_rendezvous_stream(const edge_connection_t *conn);
  int connection_ap_can_use_exit(const entry_connection_t *conn,
                                 const node_t *exit);
  void connection_ap_expire_beginning(void);
  void connection_ap_rescan_and_attach_pending(void);
  void connection_ap_attach_pending(int retry);
  void connection_ap_mark_as_pending_circuit_(entry_connection_t *entry_conn,
                                             const char *file, int line);
  #define connection_ap_mark_as_pending_circuit(c) \
    connection_ap_mark_as_pending_circuit_((c), __FILE__, __LINE__)
  void connection_ap_mark_as_non_pending_circuit(entry_connection_t *entry_conn);
  void connection_ap_mark_as_waiting_for_renddesc(
                                         entry_connection_t *entry_conn);
  
  #define CONNECTION_AP_EXPECT_NONPENDING(c) do {                         \
      if (ENTRY_TO_CONN(c)->state == AP_CONN_STATE_CIRCUIT_WAIT) {        \
        log_warn(LD_BUG, "At %s:%d: %p was unexpectedly in circuit_wait.", \
                 __FILE__, __LINE__, (c));                                \
        connection_ap_mark_as_non_pending_circuit(c);                     \
      }                                                                   \
    } while (0)
  void connection_ap_fail_onehop(const char *failed_digest,
                                 cpath_build_state_t *build_state);
  void circuit_discard_optional_exit_enclaves(extend_info_t *info);
  int connection_ap_detach_retriable(entry_connection_t *conn,
                                     origin_circuit_t *circ,
                                     int reason);
  int connection_ap_process_transparent(entry_connection_t *conn);
  
  int address_is_invalid_destination(const char *address, int client);
  
  MOCK_DECL(int, connection_ap_rewrite_and_attach_if_allowed,
                                                  (entry_connection_t *conn,
                                                   origin_circuit_t *circ,
                                                   crypt_path_t *cpath));
  int connection_ap_handshake_rewrite_and_attach(entry_connection_t *conn,
                                                 origin_circuit_t *circ,
                                                 crypt_path_t *cpath);
  
  #if defined(HAVE_NET_IF_H) && defined(HAVE_NET_PFVAR_H)
  int get_pf_socket(void);
  #endif
  
  int connection_edge_compatible_with_circuit(const entry_connection_t *conn,
                                              const origin_circuit_t *circ);
  int connection_edge_update_circuit_isolation(const entry_connection_t *conn,
                                               origin_circuit_t *circ,
                                               int dry_run);
  void circuit_clear_isolation(origin_circuit_t *circ);
  streamid_t get_unique_stream_id_by_circ(origin_circuit_t *circ);
  
  void connection_edge_free_all(void);
  
  void connection_ap_warn_and_unmark_if_pending_circ(
                                               entry_connection_t *entry_conn,
                                               const char *where);
  
  int connection_half_edge_is_valid_data(const smartlist_t *half_conns,
                                         streamid_t stream_id);
  int connection_half_edge_is_valid_sendme(const smartlist_t *half_conns,
                                           streamid_t stream_id);
  int connection_half_edge_is_valid_connected(const smartlist_t *half_conns,
                                              streamid_t stream_id);
  int connection_half_edge_is_valid_end(smartlist_t *half_conns,
                                        streamid_t stream_id);
  int connection_half_edge_is_valid_resolved(smartlist_t *half_conns,
                                             streamid_t stream_id);
  
  size_t half_streams_get_total_allocation(void);
  struct half_edge_t;
  void half_edge_free_(struct half_edge_t *he);
  #define half_edge_free(he) \
    FREE_AND_NULL(half_edge_t, half_edge_free_, (he))
  
  /** @name Begin-cell flags
   *
   * These flags are used in RELAY_BEGIN cells to change the default behavior
   * of the cell.
   *
   * @{
   **/
  /** When this flag is set, the client is willing to get connected to IPv6
   * addresses */
  #define BEGIN_FLAG_IPV6_OK        (1u<<0)
  /** When this flag is set, the client DOES NOT support connecting to IPv4
   * addresses.  (The sense of this flag is inverted from IPV6_OK, so that the
   * old default behavior of Tor is equivalent to having all flags set to 0.)
   **/
  #define BEGIN_FLAG_IPV4_NOT_OK    (1u<<1)
  /** When this flag is set, if we find both an IPv4 and an IPv6 address,
   * we use the IPv6 address.  Otherwise we use the IPv4 address. */
  #define BEGIN_FLAG_IPV6_PREFERRED (1u<<2)
  /**@}*/
  
  #ifdef CONNECTION_EDGE_PRIVATE
  
  STATIC bool parse_extended_hostname(char *address, hostname_type_t *type_out);
  
  /** A parsed BEGIN or BEGIN_DIR cell */
  typedef struct begin_cell_t {
    /** The address the client has asked us to connect to, or NULL if this is
     * a BEGIN_DIR cell*/
    char *address;
    /** The flags specified in the BEGIN cell's body.  One or more of
     * BEGIN_FLAG_*. */
    uint32_t flags;
    /** The client's requested port. */
    uint16_t port;
    /** The client's requested Stream ID */
    uint16_t stream_id;
    /** True iff this is a BEGIN_DIR cell. */
    unsigned is_begindir : 1;
  } begin_cell_t;
  
  STATIC int begin_cell_parse(const cell_t *cell, begin_cell_t *bcell,
                       uint8_t *end_reason_out);
  STATIC int connected_cell_format_payload(uint8_t *payload_out,
                                    const tor_addr_t *addr,
                                    uint32_t ttl);
  
  typedef struct {
    /** Original address, after we lowercased it but before we started
     * mapping it.
     */
    char orig_address[MAX_SOCKS_ADDR_LEN];
    /** True iff the address has been automatically remapped to a local
     * address in VirtualAddrNetwork.  (Only set true when we do a resolve
     * and get a virtual address; not when we connect to the address.) */
    int automap;
    /** If this connection has a .exit address, who put it there? */
    addressmap_entry_source_t exit_source;
    /** If we've rewritten the address, when does this map expire? */
    time_t map_expires;
    /** If we should close the connection, this is the end_reason to pass
     * to connection_mark_unattached_ap */
    int end_reason;
    /** True iff we should close the connection, either because of error or
     * because of successful early RESOLVED reply. */
    int should_close;
  } rewrite_result_t;
  
  STATIC void connection_ap_handshake_rewrite(entry_connection_t *conn,
                                              rewrite_result_t *out);
  
  STATIC int connection_ap_process_http_connect(entry_connection_t *conn);
  STATIC void export_hs_client_circuit_id(edge_connection_t *edge_conn,
                              hs_circuit_id_protocol_t protocol);
  
  struct half_edge_t;
  STATIC void connection_half_edge_add(const edge_connection_t *conn,
                                       origin_circuit_t *circ);
  STATIC struct half_edge_t *connection_half_edge_find_stream_id(
                                       const smartlist_t *half_conns,
                                       streamid_t stream_id);
  #endif /* defined(CONNECTION_EDGE_PRIVATE) */
  
  #endif /* !defined(TOR_CONNECTION_EDGE_H) */
  