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Tor
0.4.7.0-alpha-dev
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#include <channel.h>
Public Types | |
| enum | { CHANNEL_NOT_CLOSING = 0 , CHANNEL_CLOSE_REQUESTED , CHANNEL_CLOSE_FROM_BELOW , CHANNEL_CLOSE_FOR_ERROR } |
| enum | { SCHED_CHAN_IDLE = 0 , SCHED_CHAN_WAITING_FOR_CELLS , SCHED_CHAN_WAITING_TO_WRITE , SCHED_CHAN_PENDING } |
Public Member Functions | |
| HT_ENTRY (channel_t) gidmap_node | |
| HANDLE_ENTRY (channel, channel_t) | |
| TOR_LIST_ENTRY (channel_t) next_with_same_id | |
Data Fields | |
| uint32_t | magic |
| channel_state_t | state |
| uint64_t | global_identifier |
| unsigned char | registered:1 |
| unsigned int | has_been_open:1 |
| unsigned int | padding_enabled:1 |
| unsigned int | currently_padding:1 |
| unsigned int | pending_padding_callback:1 |
| unsigned int | is_canonical_to_peer:1 |
| channel_usage_info_t | channel_usage |
| monotime_coarse_t | next_padding_time |
| struct tor_timer_t * | padding_timer |
| struct channel_handle_t * | timer_handle |
| tor_addr_t | addr_according_to_peer |
| uint16_t | padding_timeout_low_ms |
| uint16_t | padding_timeout_high_ms |
| enum channel_t:: { ... } | reason_for_closing |
| enum channel_t:: { ... } | scheduler_state |
| int | sched_heap_idx |
| time_t | timestamp_created |
| time_t | timestamp_active |
| monotime_coarse_t | timestamp_xfer |
| void(* | free_fn )(channel_t *) |
| void(* | close )(channel_t *) |
| const char *(* | describe_transport )(channel_t *) |
| void(* | dumpstats )(channel_t *, int) |
| channel_cell_handler_fn_ptr | cell_handler |
| double(* | get_overhead_estimate )(channel_t *) |
| int(* | get_remote_addr )(const channel_t *, tor_addr_t *) |
| int(* | get_transport_name )(channel_t *chan, char **transport_out) |
| const char *(* | describe_peer )(const channel_t *) |
| int(* | has_queued_writes )(channel_t *) |
| int(* | is_canonical )(channel_t *) |
| int(* | matches_extend_info )(channel_t *, extend_info_t *) |
| int(* | matches_target )(channel_t *, const tor_addr_t *) |
| size_t(* | num_bytes_queued )(channel_t *) |
| int(* | num_cells_writeable )(channel_t *) |
| int(* | write_cell )(channel_t *, cell_t *) |
| int(* | write_packed_cell )(channel_t *, packed_cell_t *) |
| int(* | write_var_cell )(channel_t *, var_cell_t *) |
| char | identity_digest [DIGEST_LEN] |
| struct ed25519_public_key_t | ed25519_identity |
| circuitmux_t * | cmux |
| circ_id_type_bitfield_t | circ_id_type:2 |
| unsigned | wide_circ_ids:1 |
| unsigned int | num_n_circuits |
| unsigned int | num_p_circuits |
| unsigned int | is_bad_for_new_circs:1 |
| unsigned int | is_client:1 |
| unsigned int | is_incoming:1 |
| unsigned int | is_local:1 |
| ratelim_t | last_warned_circ_ids_exhausted |
| time_t | timestamp_client |
| time_t | timestamp_recv |
| time_t | timestamp_xmit |
| time_t | timestamp_last_had_circuits |
| uint64_t | dirreq_id |
| uint64_t | n_cells_recved |
| uint64_t | n_bytes_recved |
| uint64_t | n_cells_xmitted |
| uint64_t | n_bytes_xmitted |
Channel struct; see the channel_t typedef in or.h. A channel is an abstract interface for the OR-to-OR connection, similar to connection_or_t, but without the strong coupling to the underlying TLS implementation. They are constructed by calling a protocol-specific function to open a channel to a particular node, and once constructed support the abstract operations defined below.
| anonymous enum |
State variable for use by the scheduler
| HANDLE_ENTRY | ( | channel | , |
| channel_t | |||
| ) |
Handle entry for handle-based lookup
| HT_ENTRY | ( | channel_t | ) |
List entry for hashtable for global-identifier lookup.
| TOR_LIST_ENTRY | ( | channel_t | ) |
Linked list of channels with the same RSA identity digest, for use with the digest->channel map
| tor_addr_t addr_according_to_peer |
| channel_cell_handler_fn_ptr cell_handler |
| channel_usage_info_t channel_usage |
Has this channel ever been used for non-directory traffic? Used to decide what channels to pad, and when.
Definition at line 228 of file channel.h.
Referenced by channelpadding_decide_to_pad_channel().
| circ_id_type_bitfield_t circ_id_type |
Circuit ID generation stuff for use by circuitbuild.c When we send CREATE cells along this connection, which half of the space should we use?
Definition at line 405 of file channel.h.
Referenced by channel_set_circid_type(), and get_unique_circ_id_by_chan().
| void(* close) (channel_t *) |
Close an open channel
Definition at line 318 of file channel.h.
Referenced by channel_mark_for_close().
| circuitmux_t* cmux |
Circuit mux for circuits sending on this channel
Definition at line 397 of file channel.h.
Referenced by channel_flush_from_first_active_circuit(), channel_more_to_flush(), channel_unlink_all_circuits(), circuit_about_to_free_atexit(), circuit_clear_cell_queue(), scheduler_compare_channels(), and update_circuit_on_cmux_().
| unsigned int currently_padding |
| const char*(* describe_peer) (const channel_t *) |
Get a human-readable text description of the remote endpoint, for logging.
Definition at line 346 of file channel.h.
Referenced by channel_describe_peer().
| const char*(* describe_transport) (channel_t *) |
Describe the transport subclass for this channel
Definition at line 320 of file channel.h.
Referenced by channel_describe_transport().
| uint64_t dirreq_id |
Unique ID for measuring direct network status requests;vtunneled ones come over a circuit_t, which has a dirreq_id field as well, but is a distinct namespace.
Definition at line 453 of file channel.h.
Referenced by channel_notify_flushed().
| void(* dumpstats) (channel_t *, int) |
Optional method to dump transport-specific statistics on the channel
Definition at line 322 of file channel.h.
Referenced by channel_dump_transport_statistics().
| struct ed25519_public_key_t ed25519_identity |
Ed25519 key for the other side of this channel – or zeroes if we don't have an Ed25519 identity in mind for the other side, and it hasn't shown us one.
Note that this is the identity that we hope the other side has – not necessarily its true identity. Don't believe this identity unless authentication has happened.
Definition at line 378 of file channel.h.
Referenced by connection_or_client_learned_peer_id().
| double(* get_overhead_estimate) (channel_t *) |
| uint64_t global_identifier |
Globally unique ID number for a channel over the lifetime of a Tor process. This may not be 0.
Definition at line 197 of file channel.h.
Referenced by channel_dump_statistics(), channel_find_by_global_id(), channel_init(), channel_register(), channelpadding_reduce_padding_on_channel(), circpad_estimate_circ_rtt_on_received(), circuitmux_attach_circuit(), circuitmux_detach_circuit(), circuitmux_find_map_entry(), and format_cell_stats().
| unsigned int has_been_open |
has this channel ever been open?
Definition at line 203 of file channel.h.
Referenced by channel_change_state_open().
| int(* has_queued_writes) (channel_t *) |
Check if the lower layer has queued writes
Definition at line 348 of file channel.h.
Referenced by channel_has_queued_writes().
| char identity_digest[DIGEST_LEN] |
Hash of the public RSA key for the other side's RSA identity key – or zeroes if we don't have an RSA identity in mind for the other side, and it hasn't shown us one.
Note that this is the RSA identity that we hope the other side has – not necessarily its true identity. Don't believe this identity unless authentication has happened.
Definition at line 378 of file channel.h.
Referenced by channel_do_open_actions(), channel_dump_statistics(), channel_get_for_extend(), and circuit_get_all_pending_on_channel().
| unsigned int is_bad_for_new_circs |
True iff this channel shouldn't get any new circs attached to it, because the connection is too old, or because there's a better one. More generally, this flag is used to note an unhealthy connection; for example, if a bad connection fails we shouldn't assume that the router itself has a problem.
Definition at line 419 of file channel.h.
Referenced by channel_is_bad_for_new_circs(), and channel_mark_bad_for_new_circs().
| int(* is_canonical) (channel_t *) |
Ask the lower layer if this is 'canonical', for a transport-specific definition of canonical.
Definition at line 353 of file channel.h.
Referenced by channel_is_canonical().
| unsigned int is_canonical_to_peer |
Is our peer likely to consider this channel canonical?
Definition at line 224 of file channel.h.
Referenced by channel_is_better().
| unsigned int is_client |
True iff we have decided that the other end of this connection is a client or bridge relay. Connections with this flag set should never be used to satisfy an EXTEND request.
Definition at line 424 of file channel.h.
Referenced by channel_clear_client(), channel_is_client(), and channel_mark_client().
| unsigned int is_incoming |
Set if the channel was initiated remotely (came from a listener)
Definition at line 427 of file channel.h.
Referenced by channel_is_incoming(), channel_is_outgoing(), channel_mark_incoming(), and channel_mark_outgoing().
| unsigned int is_local |
Set by lower layer if this is local; i.e., everything it communicates with for this channel returns true for is_local_addr(). This is used to decide whether to declare reachability when we receive something on this channel in circuitbuild.c
Definition at line 434 of file channel.h.
Referenced by channel_is_local(), channel_mark_local(), and channel_mark_remote().
| ratelim_t last_warned_circ_ids_exhausted |
| uint32_t magic |
Magic number for type-checking cast macros
Definition at line 183 of file channel.h.
Referenced by channel_tls_common_init(), and channel_tls_from_base().
| int(* matches_extend_info) (channel_t *, extend_info_t *) |
Check if this channel matches a specified extend_info_t
Definition at line 355 of file channel.h.
Referenced by channel_matches_extend_info().
| int(* matches_target) (channel_t *, const tor_addr_t *) |
Check if this channel matches a target address when extending
Definition at line 357 of file channel.h.
Referenced by channel_matches_target_addr_for_extend().
| uint64_t n_cells_recved |
| uint64_t n_cells_xmitted |
| monotime_coarse_t next_padding_time |
| unsigned int num_n_circuits |
For how many circuits are we n_chan? What about p_chan?
Definition at line 410 of file channel.h.
Referenced by channel_num_circuits(), and channel_unlink_all_circuits().
| unsigned int padding_enabled |
This field indicates if the other side has enabled or disabled padding via either the link protocol version or channelpadding_negotiate cells.
Clients can override this with ConnectionPadding in torrc to disable or force padding to relays, but relays cannot override the client's request.
Definition at line 214 of file channel.h.
Referenced by channelpadding_disable_padding_on_channel(), and channelpadding_reduce_padding_on_channel().
| uint16_t padding_timeout_low_ms |
These two fields specify the minimum and maximum negotiated timeout values for inactivity (send or receive) before we decide to pad a channel. These fields can be set either via a PADDING_NEGOTIATE cell, or the torrc option ReducedConnectionPadding. The consensus parameters nf_ito_low and nf_ito_high are used to ensure that padding can only be negotiated to be less frequent than what is specified in the consensus. (This is done to prevent wingnut clients from requesting excessive padding).
The actual timeout value is randomly chosen between these two values as per the table in channelpadding_get_netflow_inactive_timeout_ms(), after ensuring that these values do not specify lower timeouts than the consensus parameters.
If these are 0, we have not negotiated or specified custom padding times, and instead use consensus defaults.
Definition at line 259 of file channel.h.
Referenced by channelpadding_get_netflow_inactive_timeout_ms(), and channelpadding_reduce_padding_on_channel().
| struct tor_timer_t* padding_timer |
| unsigned int pending_padding_callback |
Is there a pending netflow padding callback?
Definition at line 221 of file channel.h.
Referenced by channelpadding_schedule_padding(), and channelpadding_send_padding_cell_for_callback().
| enum { ... } reason_for_closing |
Why did we close?
| unsigned char registered |
Should we expect to see this channel in the channel lists?
Definition at line 200 of file channel.h.
Referenced by channel_register(), and channel_unregister().
| int sched_heap_idx |
Heap index for use by the scheduler
Definition at line 295 of file channel.h.
Referenced by scheduler_channel_has_waiting_cells(), and scheduler_channel_wants_writes().
| enum { ... } scheduler_state |
State variable for use by the scheduler
Referenced by scheduler_channel_doesnt_want_writes(), scheduler_channel_has_waiting_cells(), and scheduler_channel_wants_writes().
| channel_state_t state |
Current channel state
Definition at line 192 of file channel.h.
Referenced by channel_change_state_(), channel_dump_statistics(), channel_num_cells_writeable(), channelpadding_decide_to_pad_channel(), and channelpadding_send_padding_cell_for_callback().
| struct channel_handle_t* timer_handle |
| time_t timestamp_client |
Channel timestamps for cell channels
Definition at line 441 of file channel.h.
Referenced by channel_timestamp_client(), and channel_when_last_client().
| time_t timestamp_created |
Timestamps for both cell channels and listeners
Definition at line 298 of file channel.h.
Referenced by channel_dump_statistics(), channel_timestamp_created(), and channel_when_created().
| time_t timestamp_last_had_circuits |
Timestamp for run_connection_housekeeping(). We update this once a second when we run housekeeping and find a circuit on this channel, and whenever we add a circuit to the channel.
Definition at line 448 of file channel.h.
Referenced by circuit_set_n_circid_chan(), and circuit_set_p_circid_chan().
| monotime_coarse_t timestamp_xfer |
This is a monotonic timestamp that marks when we believe the channel has actually sent or received data to/from the wire. Right now, it is used to determine when we should send a padding cell for channelpadding.
XXX: Are we setting timestamp_xfer_ms in the right places to accurately reflect actual network data transfer? Or might this be very wrong wrt when bytes actually go on the wire?
| time_t timestamp_xmit |
Cell sent to lower layer
Definition at line 443 of file channel.h.
Referenced by channel_when_last_xmit().
| int(* write_packed_cell) (channel_t *, packed_cell_t *) |
| int(* write_var_cell) (channel_t *, var_cell_t *) |
1.9.1