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Tor
0.4.7.0-alpha-dev
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#include <circuitpadding.h>
Data Fields | |
| tor_timer_t * | padding_timer |
| struct circuit_t * | on_circ |
| circpad_hist_token_t * | histogram |
| circpad_hist_index_t | histogram_len |
| circpad_hist_index_t | chosen_bin |
| uint64_t | state_length |
| uint16_t | padding_sent |
| uint16_t | nonpadding_sent |
| time_t | last_cell_time_sec |
| circpad_delay_t | rtt_estimate_usec |
| circpad_time_t | last_received_time_usec |
| circpad_time_t | padding_scheduled_at_usec |
| circpad_statenum_t | current_state |
| uint32_t | machine_ctr |
| unsigned | is_padding_timer_scheduled: 1 |
| unsigned | stop_rtt_update: 1 |
| unsigned | machine_index: 1 |
Mutable padding machine info.
This structure contains mutable information about a padding machine. The mutable information must be kept separate because it exists per-circuit, where as the machines themselves are global. This separation is done to conserve space in the circuit structure.
This is the per-circuit state that changes regarding the global state machine. Some parts of it are optional (ie NULL).
XXX: Play with layout to minimize space on x64 Linux (most common relay).
Definition at line 509 of file circuitpadding.h.
| circpad_hist_index_t chosen_bin |
Remove token from this index upon sending padding
Definition at line 532 of file circuitpadding.h.
| circpad_statenum_t current_state |
What state is this machine in?
Definition at line 576 of file circuitpadding.h.
Referenced by circpad_machine_current_state(), and circpad_send_padding_cell_for_callback().
| circpad_hist_token_t* histogram |
A mutable copy of the histogram for the current state. NULL if remove_tokens is false for that state
Definition at line 523 of file circuitpadding.h.
Referenced by check_machine_token_supply(), circpad_circuit_machineinfo_free_idx(), circpad_is_token_removal_supported(), circpad_machine_first_higher_index(), circpad_machine_first_lower_index(), circpad_machine_remove_exact(), and circpad_machine_setup_tokens().
| circpad_hist_index_t histogram_len |
Length of the above histogram. XXX: This field could be removed at the expense of added complexity+overhead for reaching back into the immutable machine state every time we need to inspect the histogram. It's only a byte, though, so it seemed worth it.
Definition at line 530 of file circuitpadding.h.
Referenced by circpad_machine_first_higher_index(), and circpad_machine_setup_tokens().
| unsigned is_padding_timer_scheduled |
True if we have scheduled a timer for padding.
This is 1 if a timer is pending. It is 0 if no timer is scheduled. (It can be 0 even when padding_was_scheduled_at_usec is non-zero).
Definition at line 592 of file circuitpadding.h.
Referenced by circpad_send_padding_cell_for_callback().
| time_t last_cell_time_sec |
Timestamp of the most recent cell event (sent, received, padding, non-padding), in seconds from approx_time().
Used as an emergency break to stop holding padding circuits open.
Definition at line 552 of file circuitpadding.h.
Referenced by circpad_cell_event_nonpadding_received(), and circpad_cell_event_padding_received().
| circpad_time_t last_received_time_usec |
The last time we got an event relevant to estimating the RTT. Monotonic time in microseconds since system start.
Definition at line 564 of file circuitpadding.h.
Referenced by circpad_estimate_circ_rtt_on_received(), and circpad_estimate_circ_rtt_on_send().
| uint32_t machine_ctr |
Machine counter, for shutdown sync.
Set from circuit_t.padding_machine_ctr, which is incremented each padding machine instantiation.
Definition at line 583 of file circuitpadding.h.
Referenced by circpad_machine_spec_transitioned_to_end(), circpad_shutdown_old_machines(), and free_circ_machineinfos_with_machine_num().
| unsigned machine_index |
Which padding machine index was this for. (make sure changes to the bitwidth can support the CIRCPAD_MAX_MACHINES define).
Definition at line 606 of file circuitpadding.h.
Referenced by circpad_send_padding_cell_for_callback().
| uint16_t nonpadding_sent |
A scaled count of non-padding packets sent, used to limit padding overhead. When this reaches UINT16_MAX, we cut it and padding_sent in half.
Definition at line 544 of file circuitpadding.h.
Referenced by circpad_machine_count_nonpadding_sent(), and circpad_machine_reached_padding_limit().
| struct circuit_t* on_circ |
The circuit for this machine
Definition at line 519 of file circuitpadding.h.
Referenced by circpad_machine_spec_transitioned_to_end(), and circpad_send_padding_cell_for_callback().
| circpad_time_t padding_scheduled_at_usec |
The time at which we scheduled a non-padding packet, or selected an infinite delay.
Monotonic time in microseconds since system start. This is 0 if we haven't chosen a padding delay.
Definition at line 573 of file circuitpadding.h.
Referenced by circpad_machine_remove_token(), and circpad_send_padding_cell_for_callback().
| uint16_t padding_sent |
A scaled count of padding packets sent, used to limit padding overhead. When this reaches UINT16_MAX, we cut it and nonpadding_sent in half.
Definition at line 540 of file circuitpadding.h.
Referenced by circpad_machine_count_nonpadding_sent(), and circpad_machine_reached_padding_limit().
| tor_timer_t* padding_timer |
The callback pointer for the padding callbacks.
These timers stick around the machineinfo until the machineinfo's circuit is closed, at which point the timer is cancelled. For this reason it's safe to assume that the machineinfo exists if this timer gets triggered.
Definition at line 516 of file circuitpadding.h.
| circpad_delay_t rtt_estimate_usec |
EWMA estimate of the RTT of the circuit from this hop to the exit end, in microseconds.
Definition at line 557 of file circuitpadding.h.
Referenced by circpad_estimate_circ_rtt_on_received(), and circpad_estimate_circ_rtt_on_send().
| uint64_t state_length |
Stop padding/transition if this many cells sent
Definition at line 535 of file circuitpadding.h.
Referenced by circpad_machine_count_padding_sent(), and circpad_machine_update_state_length_for_nonpadding().
| unsigned stop_rtt_update |
If this is true, we have seen full duplex behavior. Stop updating the RTT.
Definition at line 598 of file circuitpadding.h.
Referenced by circpad_estimate_circ_rtt_on_received(), and circpad_estimate_circ_rtt_on_send().
1.9.1