src/core/or/connection_edge.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 connection_edge.h
   9  * \brief Header file for connection_edge.c.
  10  **/
  11
  12 #ifndef TOR_CONNECTION_EDGE_H
  13 #define TOR_CONNECTION_EDGE_H
  14
  15 #include "lib/testsupport/testsupport.h"
  16
  17 #include "feature/hs/hs_service.h"
  18
  19 edge_connection_t *TO_EDGE_CONN(connection_t *);
  20 entry_connection_t *TO_ENTRY_CONN(connection_t *);
  21 entry_connection_t *EDGE_TO_ENTRY_CONN(edge_connection_t *);
  22
  23 const edge_connection_t *CONST_TO_EDGE_CONN(const connection_t *);
  24 const entry_connection_t *CONST_TO_ENTRY_CONN(const connection_t *);
  25 const entry_connection_t *CONST_EDGE_TO_ENTRY_CONN(const edge_connection_t *);
  26
  27 #define EXIT_CONN_STATE_MIN_ 1
  28 /** State for an exit connection: waiting for response from DNS farm. */
  29 #define EXIT_CONN_STATE_RESOLVING 1
  30 /** State for an exit connection: waiting for connect() to finish. */
  31 #define EXIT_CONN_STATE_CONNECTING 2
  32 /** State for an exit connection: open and ready to transmit data. */
  33 #define EXIT_CONN_STATE_OPEN 3
  34 /** State for an exit connection: waiting to be removed. */
  35 #define EXIT_CONN_STATE_RESOLVEFAILED 4
  36 #define EXIT_CONN_STATE_MAX_ 4
  37
  38 /* The AP state values must be disjoint from the EXIT state values. */
  39 #define AP_CONN_STATE_MIN_ 5
  40 /** State for a SOCKS connection: waiting for SOCKS request. */
  41 #define AP_CONN_STATE_SOCKS_WAIT 5
  42 /** State for a SOCKS connection: got a y.onion URL; waiting to receive
  43  * rendezvous descriptor. */
  44 #define AP_CONN_STATE_RENDDESC_WAIT 6
  45 /** The controller will attach this connection to a circuit; it isn't our
  46  * job to do so. */
  47 #define AP_CONN_STATE_CONTROLLER_WAIT 7
  48 /** State for a SOCKS connection: waiting for a completed circuit. */
  49 #define AP_CONN_STATE_CIRCUIT_WAIT 8
  50 /** State for a SOCKS connection: sent BEGIN, waiting for CONNECTED. */
  51 #define AP_CONN_STATE_CONNECT_WAIT 9
  52 /** State for a SOCKS connection: sent RESOLVE, waiting for RESOLVED. */
  53 #define AP_CONN_STATE_RESOLVE_WAIT 10
  54 /** State for a SOCKS connection: ready to send and receive. */
  55 #define AP_CONN_STATE_OPEN 11
  56 /** State for a transparent natd connection: waiting for original
  57  * destination. */
  58 #define AP_CONN_STATE_NATD_WAIT 12
  59 /** State for an HTTP tunnel: waiting for an HTTP CONNECT command. */
  60 #define AP_CONN_STATE_HTTP_CONNECT_WAIT 13
  61 #define AP_CONN_STATE_MAX_ 13
  62
  63 #define EXIT_PURPOSE_MIN_ 1
  64 /** This exit stream wants to do an ordinary connect. */
  65 #define EXIT_PURPOSE_CONNECT 1
  66 /** This exit stream wants to do a resolve (either normal or reverse). */
  67 #define EXIT_PURPOSE_RESOLVE 2
  68 #define EXIT_PURPOSE_MAX_ 2
  69
  70 /** True iff the AP_CONN_STATE_* value <b>s</b> means that the corresponding
  71  * edge connection is not attached to any circuit. */
  72 #define AP_CONN_STATE_IS_UNATTACHED(s) \
  73   ((s) <= AP_CONN_STATE_CIRCUIT_WAIT || (s) == AP_CONN_STATE_NATD_WAIT)
  74
  75 #define connection_mark_unattached_ap(conn, endreason)                  \
  76   connection_mark_unattached_ap_((conn), (endreason), __LINE__, SHORT_FILE__)
  77
  78 /** Possible return values for parse_extended_hostname. */
  79 typedef enum hostname_type_t {
  80   BAD_HOSTNAME,
  81   EXIT_HOSTNAME,
  82   NORMAL_HOSTNAME,
  83   ONION_V3_HOSTNAME,
  84 } hostname_type_t;
  85
  86 MOCK_DECL(void,connection_mark_unattached_ap_,
  87           (entry_connection_t *conn, int endreason,
  88            int line, const char *file));
  89 int connection_edge_reached_eof(edge_connection_t *conn);
  90 int connection_edge_process_inbuf(edge_connection_t *conn,
  91                                   int package_partial);
  92 int connection_edge_destroy(circid_t circ_id, edge_connection_t *conn);
  93 int connection_edge_end(edge_connection_t *conn, uint8_t reason);
  94 int connection_edge_end_errno(edge_connection_t *conn);
  95 void connection_edge_end_close(edge_connection_t *conn, uint8_t reason);
  96 int connection_edge_flushed_some(edge_connection_t *conn);
  97 int connection_edge_finished_flushing(edge_connection_t *conn);
  98 int connection_edge_finished_connecting(edge_connection_t *conn);
  99
 100 void connection_entry_set_controller_wait(entry_connection_t *conn);
 101
 102 void connection_ap_about_to_close(entry_connection_t *edge_conn);
 103 void connection_exit_about_to_close(edge_connection_t *edge_conn);
 104
 105 MOCK_DECL(int,
 106           connection_ap_handshake_send_begin,(entry_connection_t *ap_conn));
 107 int connection_ap_handshake_send_resolve(entry_connection_t *ap_conn);
 108
 109 entry_connection_t  *connection_ap_make_link(connection_t *partner,
 110                                             char *address, uint16_t port,
 111                                             const char *digest,
 112                                             int session_group,
 113                                             int isolation_flags,
 114                                             int use_begindir, int want_onehop);
 115 void connection_ap_handshake_socks_reply(entry_connection_t *conn, char *reply,
 116                                          size_t replylen,
 117                                          int endreason);
 118 MOCK_DECL(void,connection_ap_handshake_socks_resolved,
 119           (entry_connection_t *conn,
 120            int answer_type,
 121            size_t answer_len,
 122            const uint8_t *answer,
 123            int ttl,
 124            time_t expires));
 125 void connection_ap_handshake_socks_resolved_addr(entry_connection_t *conn,
 126                                                  const tor_addr_t *answer,
 127                                                  int ttl,
 128                                                  time_t expires);
 129
 130 int connection_exit_begin_conn(cell_t *cell, circuit_t *circ);
 131 int connection_exit_begin_resolve(cell_t *cell, or_circuit_t *circ);
 132 void connection_exit_connect(edge_connection_t *conn);
 133 int connection_edge_is_rendezvous_stream(const edge_connection_t *conn);
 134 int connection_ap_can_use_exit(const entry_connection_t *conn,
 135                                const node_t *exit);
 136 void connection_ap_expire_beginning(void);
 137 void connection_ap_rescan_and_attach_pending(void);
 138 void connection_ap_attach_pending(int retry);
 139 void connection_ap_mark_as_pending_circuit_(entry_connection_t *entry_conn,
 140                                            const char *file, int line);
 141 #define connection_ap_mark_as_pending_circuit(c) \
 142   connection_ap_mark_as_pending_circuit_((c), __FILE__, __LINE__)
 143 void connection_ap_mark_as_non_pending_circuit(entry_connection_t *entry_conn);
 144 void connection_ap_mark_as_waiting_for_renddesc(
 145                                        entry_connection_t *entry_conn);
 146
 147 #define CONNECTION_AP_EXPECT_NONPENDING(c) do {                         \
 148     if (ENTRY_TO_CONN(c)->state == AP_CONN_STATE_CIRCUIT_WAIT) {        \
 149       log_warn(LD_BUG, "At %s:%d: %p was unexpectedly in circuit_wait.", \
 150                __FILE__, __LINE__, (c));                                \
 151       connection_ap_mark_as_non_pending_circuit(c);                     \
 152     }                                                                   \
 153   } while (0)
 154 void connection_ap_fail_onehop(const char *failed_digest,
 155                                cpath_build_state_t *build_state);
 156 void circuit_discard_optional_exit_enclaves(extend_info_t *info);
 157 int connection_ap_detach_retriable(entry_connection_t *conn,
 158                                    origin_circuit_t *circ,
 159                                    int reason);
 160 int connection_ap_process_transparent(entry_connection_t *conn);
 161
 162 int address_is_invalid_destination(const char *address, int client);
 163
 164 MOCK_DECL(int, connection_ap_rewrite_and_attach_if_allowed,
 165                                                 (entry_connection_t *conn,
 166                                                  origin_circuit_t *circ,
 167                                                  crypt_path_t *cpath));
 168 int connection_ap_handshake_rewrite_and_attach(entry_connection_t *conn,
 169                                                origin_circuit_t *circ,
 170                                                crypt_path_t *cpath);
 171
 172 #if defined(HAVE_NET_IF_H) && defined(HAVE_NET_PFVAR_H)
 173 int get_pf_socket(void);
 174 #endif
 175
 176 int connection_edge_compatible_with_circuit(const entry_connection_t *conn,
 177                                             const origin_circuit_t *circ);
 178 int connection_edge_update_circuit_isolation(const entry_connection_t *conn,
 179                                              origin_circuit_t *circ,
 180                                              int dry_run);
 181 void circuit_clear_isolation(origin_circuit_t *circ);
 182 streamid_t get_unique_stream_id_by_circ(origin_circuit_t *circ);
 183
 184 void connection_edge_free_all(void);
 185
 186 void connection_ap_warn_and_unmark_if_pending_circ(
 187                                              entry_connection_t *entry_conn,
 188                                              const char *where);
 189
 190 /** Lowest value for DNS ttl clipping excluding the random addition. */
 191 #define MIN_DNS_TTL (5*60)
 192 /** Highest value for DNS ttl clipping excluding the random addition. */
 193 #define MAX_DNS_TTL (60*60)
 194 /** How long do we keep DNS cache entries before purging them (regardless of
 195  * their TTL)? */
 196 #define MAX_DNS_ENTRY_AGE (3*60*60)
 197 /** How long do we cache/tell clients to cache DNS records when no TTL is
 198  * known? */
 199 #define DEFAULT_DNS_TTL (30*60)
 200 /** How much should we +- each TTL to make it fuzzy with uniform sampling at
 201  * exits?  The value 4 minutes was chosen so that the lowest possible clip is
 202  * 60s.  Such low clips were used in the past for all TTLs due to a bug in Tor,
 203  * see "The effect of DNS on Tor's Anonymity" by Greschbach et al.  In other
 204  * words, sampling such low clips is unlikely to cause any breakage at exits.
 205  */
 206 #define FUZZY_DNS_TTL (4*60)
 207
 208 uint32_t clip_dns_ttl(uint32_t ttl);
 209 uint32_t clip_dns_fuzzy_ttl(uint32_t ttl);
 210
 211 int connection_half_edge_is_valid_data(const smartlist_t *half_conns,
 212                                        streamid_t stream_id);
 213 int connection_half_edge_is_valid_sendme(const smartlist_t *half_conns,
 214                                          streamid_t stream_id);
 215 int connection_half_edge_is_valid_connected(const smartlist_t *half_conns,
 216                                             streamid_t stream_id);
 217 int connection_half_edge_is_valid_end(smartlist_t *half_conns,
 218                                       streamid_t stream_id);
 219 int connection_half_edge_is_valid_resolved(smartlist_t *half_conns,
 220                                            streamid_t stream_id);
 221 bool connection_half_edges_waiting(const origin_circuit_t *circ);
 222
 223 size_t half_streams_get_total_allocation(void);
 224 struct half_edge_t;
 225 void half_edge_free_(struct half_edge_t *he);
 226 #define half_edge_free(he) \
 227   FREE_AND_NULL(half_edge_t, half_edge_free_, (he))
 228
 229 /** @name Begin-cell flags
 230  *
 231  * These flags are used in RELAY_BEGIN cells to change the default behavior
 232  * of the cell.
 233  *
 234  * @{
 235  **/
 236 /** When this flag is set, the client is willing to get connected to IPv6
 237  * addresses */
 238 #define BEGIN_FLAG_IPV6_OK        (1u<<0)
 239 /** When this flag is set, the client DOES NOT support connecting to IPv4
 240  * addresses.  (The sense of this flag is inverted from IPV6_OK, so that the
 241  * old default behavior of Tor is equivalent to having all flags set to 0.)
 242  **/
 243 #define BEGIN_FLAG_IPV4_NOT_OK    (1u<<1)
 244 /** When this flag is set, if we find both an IPv4 and an IPv6 address,
 245  * we use the IPv6 address.  Otherwise we use the IPv4 address. */
 246 #define BEGIN_FLAG_IPV6_PREFERRED (1u<<2)
 247 /**@}*/
 248
 249 #ifdef CONNECTION_EDGE_PRIVATE
 250
 251 STATIC bool parse_extended_hostname(char *address, hostname_type_t *type_out);
 252
 253 /** A parsed BEGIN or BEGIN_DIR cell */
 254 typedef struct begin_cell_t {
 255   /** The address the client has asked us to connect to, or NULL if this is
 256    * a BEGIN_DIR cell*/
 257   char *address;
 258   /** The flags specified in the BEGIN cell's body.  One or more of
 259    * BEGIN_FLAG_*. */
 260   uint32_t flags;
 261   /** The client's requested port. */
 262   uint16_t port;
 263   /** The client's requested Stream ID */
 264   uint16_t stream_id;
 265   /** True iff this is a BEGIN_DIR cell. */
 266   unsigned is_begindir : 1;
 267 } begin_cell_t;
 268
 269 STATIC int begin_cell_parse(const cell_t *cell, begin_cell_t *bcell,
 270                      uint8_t *end_reason_out);
 271 STATIC int connected_cell_format_payload(uint8_t *payload_out,
 272                                   const tor_addr_t *addr,
 273                                   uint32_t ttl);
 274
 275 typedef struct {
 276   /** Original address, after we lowercased it but before we started
 277    * mapping it.
 278    */
 279   char orig_address[MAX_SOCKS_ADDR_LEN];
 280   /** True iff the address has been automatically remapped to a local
 281    * address in VirtualAddrNetwork.  (Only set true when we do a resolve
 282    * and get a virtual address; not when we connect to the address.) */
 283   int automap;
 284   /** If this connection has a .exit address, who put it there? */
 285   addressmap_entry_source_t exit_source;
 286   /** If we've rewritten the address, when does this map expire? */
 287   time_t map_expires;
 288   /** If we should close the connection, this is the end_reason to pass
 289    * to connection_mark_unattached_ap */
 290   int end_reason;
 291   /** True iff we should close the connection, either because of error or
 292    * because of successful early RESOLVED reply. */
 293   int should_close;
 294 } rewrite_result_t;
 295
 296 STATIC void connection_ap_handshake_rewrite(entry_connection_t *conn,
 297                                             rewrite_result_t *out);
 298
 299 STATIC int connection_ap_process_http_connect(entry_connection_t *conn);
 300 STATIC void export_hs_client_circuit_id(edge_connection_t *edge_conn,
 301                             hs_circuit_id_protocol_t protocol);
 302
 303 struct half_edge_t;
 304 STATIC void connection_half_edge_add(const edge_connection_t *conn,
 305                                      origin_circuit_t *circ);
 306 STATIC struct half_edge_t *connection_half_edge_find_stream_id(
 307                                      const smartlist_t *half_conns,
 308                                      streamid_t stream_id);
 309 #endif /* defined(CONNECTION_EDGE_PRIVATE) */
 310
 311 #endif /* !defined(TOR_CONNECTION_EDGE_H) */