#include <channel.h>
Public Member Functions | |
| HT_ENTRY (channel_s) gidmap_node | |
| HANDLE_ENTRY (channel, channel_s) | |
| TOR_LIST_ENTRY (channel_s) 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 |
| tor_timer_t * | padding_timer |
| struct channel_handle_t * | timer_handle |
| uint16_t | padding_timeout_low_ms |
| uint16_t | padding_timeout_high_ms |
| enum channel_s:: { ... } | reason_for_closing |
| enum channel_s:: { ... } | 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 |
| channel_var_cell_handler_fn_ptr | var_cell_handler |
| double(* | get_overhead_estimate )(channel_t *) |
| int(* | get_remote_addr )(channel_t *, tor_addr_t *) |
| int(* | get_transport_name )(channel_t *chan, char **transport_out) |
| const char *(* | get_remote_descr )(channel_t *, int) |
| int(* | has_queued_writes )(channel_t *) |
| int(* | is_canonical )(channel_t *, int) |
| 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] |
| 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 |
Detailed Description
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.
Member Enumeration Documentation
◆ anonymous enum
| anonymous enum |
State variable for use by the scheduler
◆ anonymous enum
| anonymous enum |
Why did we close?
Member Function Documentation
◆ HANDLE_ENTRY()
| HANDLE_ENTRY | ( | channel | , |
| channel_s | |||
| ) |
Handle entry for handle-based lookup
◆ HT_ENTRY()
| HT_ENTRY | ( | channel_s | ) |
List entry for hashtable for global-identifier lookup.
◆ TOR_LIST_ENTRY()
| TOR_LIST_ENTRY | ( | channel_s | ) |
Linked list of channels with the same RSA identity digest, for use with the digest->channel map
Field Documentation
◆ cell_handler
| channel_cell_handler_fn_ptr cell_handler |
Registered handlers for incoming cells
◆ channel_usage
| 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.
◆ circ_id_type
| 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?
◆ close
| void(* close) (channel_t *) |
Close an open channel
◆ cmux
| circuitmux_t* cmux |
Circuit mux for circuits sending on this channel
◆ currently_padding
| unsigned int currently_padding |
Cached value of our decision to pad (to avoid expensive checks during critical path statistics counting).
◆ describe_transport
| const char*(* describe_transport) (channel_t *) |
Describe the transport subclass for this channel
◆ dirreq_id
| 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.
◆ dumpstats
| void(* dumpstats) (channel_t *, int) |
Optional method to dump transport-specific statistics on the channel
◆ ed25519_identity
| 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.
◆ free_fn
| void(* free_fn) (channel_t *) |
Free a channel
◆ get_overhead_estimate
| double(* get_overhead_estimate) (channel_t *) |
Ask the lower layer for an estimate of the average overhead for transmissions on this channel.
◆ get_remote_descr
| const char*(* get_remote_descr) (channel_t *, int) |
Get a text description of the remote endpoint; canonicalized if the flag GRD_FLAG_ORIGINAL is not set, or the one we originally connected to/received from if it is. If GRD_FLAG_ADDR_ONLY is set, we return only the original address.
◆ global_identifier
| uint64_t global_identifier |
Globally unique ID number for a channel over the lifetime of a Tor process. This may not be 0.
◆ has_been_open
| unsigned int has_been_open |
has this channel ever been open?
◆ has_queued_writes
| int(* has_queued_writes) (channel_t *) |
Check if the lower layer has queued writes
◆ identity_digest
| 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.
◆ is_bad_for_new_circs
| 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.
◆ is_canonical
| int(* is_canonical) (channel_t *, int) |
If the second param is zero, ask the lower layer if this is 'canonical', for a transport-specific definition of canonical; if it is 1, ask if the answer to the preceding query is safe to rely on.
◆ is_canonical_to_peer
| unsigned int is_canonical_to_peer |
Is our peer likely to consider this channel canonical?
◆ is_client
| 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.
◆ is_incoming
| unsigned int is_incoming |
Set if the channel was initiated remotely (came from a listener)
◆ is_local
| 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
◆ last_warned_circ_ids_exhausted
| ratelim_t last_warned_circ_ids_exhausted |
Have we logged a warning about circID exhaustion on this channel? If so, when?
◆ magic
| uint32_t magic |
Magic number for type-checking cast macros
◆ matches_extend_info
| int(* matches_extend_info) (channel_t *, extend_info_t *) |
Check if this channel matches a specified extend_info_t
◆ matches_target
| int(* matches_target) (channel_t *, const tor_addr_t *) |
Check if this channel matches a target address when extending
◆ n_cells_recved
| uint64_t n_cells_recved |
Channel counters for cell channels
◆ next_padding_time
| monotime_coarse_t next_padding_time |
When should we send a cell for netflow padding? 0 means no padding is scheduled.
◆ num_n_circuits
| unsigned int num_n_circuits |
For how many circuits are we n_chan? What about p_chan?
◆ padding_enabled
| 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.
◆ padding_timeout_low_ms
| 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.
◆ padding_timer
| tor_timer_t* padding_timer |
The callback pointer for the padding callbacks
◆ pending_padding_callback
| unsigned int pending_padding_callback |
Is there a pending netflow padding callback?
◆ reason_for_closing
| enum { ... } reason_for_closing |
Why did we close?
◆ registered
| unsigned char registered |
Should we expect to see this channel in the channel lists?
◆ sched_heap_idx
| int sched_heap_idx |
Heap index for use by the scheduler
◆ scheduler_state
| enum { ... } scheduler_state |
State variable for use by the scheduler
◆ state
| channel_state_t state |
Current channel state
◆ timer_handle
| struct channel_handle_t* timer_handle |
The handle to this channel (to free on canceled timers)
◆ timestamp_client
| time_t timestamp_client |
Channel timestamps for cell channels
◆ timestamp_created
| time_t timestamp_created |
Timestamps for both cell channels and listeners
◆ timestamp_last_had_circuits
| 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.
◆ timestamp_xfer
| 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?
◆ write_packed_cell
| int(* write_packed_cell) (channel_t *, packed_cell_t *) |
Write a packed cell to an open channel
◆ write_var_cell
| int(* write_var_cell) (channel_t *, var_cell_t *) |
Write a variable-length cell to an open channel
The documentation for this struct was generated from the following file:
- /home/user/_my/code/bwauth-related/tor/src/or/channel.h
