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[tor-commits] [tor/master] Refactor rend machines, stage 2/2: Move histogram code.
commit 857c54ca038baf0881ce6859dbdb2c3446f54c50
Author: Mike Perry <mikeperry-git@xxxxxxxxxxxxxx>
Date: Thu May 16 19:42:45 2019 +0000
Refactor rend machines, stage 2/2: Move histogram code.
Comment clarifications now that the code is seperated. It's the same code, but
its doing this for different reasons on each side.
---
src/core/or/circuitpadding_machines.c | 103 +++++++++++++++++++++++-----------
1 file changed, 70 insertions(+), 33 deletions(-)
diff --git a/src/core/or/circuitpadding_machines.c b/src/core/or/circuitpadding_machines.c
index 5350e6e86..75d2614ac 100644
--- a/src/core/or/circuitpadding_machines.c
+++ b/src/core/or/circuitpadding_machines.c
@@ -255,35 +255,6 @@ circpad_machine_relay_hide_intro_circuits(smartlist_t *machines_sl)
/************************** Rendezvous-circuit machine ***********************/
-/* Setup the obf state of the machine that hides client-side rend
- * circuits. */
-static void
-setup_obf_state_for_hiding_rend_circuits(circpad_state_t *obf_state)
-{
- /* Don't use a token removal strategy since we don't want to use monotime
- functions. We want this machine to be light. */
- obf_state->token_removal = CIRCPAD_TOKEN_REMOVAL_NONE;
-
- /* Instead, to control the volume of padding (we just want to send a single
- * padding cell) we will use a static state length. We just want one token,
- * since we want to make the following pattern:
- * [PADDING_NEGOTIATE] -> [DROP] -> PADDING_NEGOTIATED -> DROP */
- obf_state->length_dist.type = CIRCPAD_DIST_UNIFORM;
- obf_state->length_dist.param1 = 1;
- obf_state->length_dist.param2 = 2;
-
- /* Histogram is: (0 msecs, 50 msecs, infinity). We want this to be fast so
- * that the incoming PADDING_NEGOTIATED cell always arrives after the
- * outgoing [DROP]. */
- obf_state->histogram_len = 2;
- obf_state->histogram_edges[0] = 0;
- obf_state->histogram_edges[1] = 1000;
-
- /* dummy amount of tokens. they don't matter. we rely on state length. */
- obf_state->histogram[0] = 1;
- obf_state->histogram_total_tokens = 1;
-}
-
/** Create a client-side padding machine that aims to hide rendezvous
* circuits.*/
void
@@ -356,8 +327,41 @@ circpad_machine_client_hide_rend_circuits(smartlist_t *machines_sl)
client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
- setup_obf_state_for_hiding_rend_circuits(
- &client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP]);
+ /* Don't use a token removal strategy since we don't want to use monotime
+ * functions and we want to avoid mallocing histogram copies. We want
+ * this machine to be light. */
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ token_removal = CIRCPAD_TOKEN_REMOVAL_NONE;
+
+ /* Instead, to control the volume of padding (we just want to send a single
+ * padding cell) we will use a static state length. We just want one token,
+ * since we want to make the following pattern:
+ * [PADDING_NEGOTIATE] -> [DROP] -> PADDING_NEGOTIATED -> DROP */
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ length_dist.type = CIRCPAD_DIST_UNIFORM;
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ length_dist.param1 = 1;
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ length_dist.param2 = 2; // rand(1,2) is always 1
+
+ /* Histogram is: (0 msecs, 1 msec, infinity). We want this to be fast so
+ * that we send our outgoing [DROP] before the PADDING_NEGOTIATED comes
+ * back from the relay side. */
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_len = 2;
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_edges[0] = 0;
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_edges[1] = 1000;
+
+ /* We want a 100% probability of choosing an inter-packet delay of
+ * between 0 and 1ms. Since we don't use token removal,
+ * the number of tokens does not matter. (And also, state_length
+ * governs how many packets we send). */
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram[0] = 1;
+ client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_total_tokens = 1;
/* Register the machine */
client_machine->machine_num = smartlist_len(machines_sl);
@@ -408,8 +412,41 @@ circpad_machine_relay_hide_rend_circuits(smartlist_t *machines_sl)
relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
- setup_obf_state_for_hiding_rend_circuits(
- &relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP]);
+ /* Don't use a token removal strategy since we don't want to use monotime
+ * functions and we want to avoid mallocing histogram copies. We want
+ * this machine to be light. */
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ token_removal = CIRCPAD_TOKEN_REMOVAL_NONE;
+
+ /* Instead, to control the volume of padding (we just want to send a single
+ * padding cell) we will use a static state length. We just want one token,
+ * since we want to make the following pattern:
+ * [PADDING_NEGOTIATE] -> [DROP] -> PADDING_NEGOTIATED -> DROP */
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ length_dist.type = CIRCPAD_DIST_UNIFORM;
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ length_dist.param1 = 1;
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ length_dist.param2 = 2; // rand(1,2) is always 1
+
+ /* Histogram is: (0 msecs, 1 msec, infinity). We want this to be fast so
+ * that the outgoing DROP cell is sent immediately after the
+ * PADDING_NEGOTIATED. */
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_len = 2;
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_edges[0] = 0;
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_edges[1] = 1000;
+
+ /* We want a 100% probability of choosing an inter-packet delay of
+ * between 0 and 1ms. Since we don't use token removal,
+ * the number of tokens does not matter. (And also, state_length
+ * governs how many packets we send). */
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram[0] = 1;
+ relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+ histogram_total_tokens = 1;
/* Register the machine */
relay_machine->machine_num = smartlist_len(machines_sl);
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