Merge remote-tracking branch 'public/feature9777_024_squashed' into maint-0.2.4

This commit is contained in:
Nick Mathewson 2014-02-24 13:05:25 -05:00
commit d21b24b3b6
4 changed files with 81 additions and 10 deletions

3
changes/feature9777 Normal file
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@ -0,0 +1,3 @@
o Minor features:
- Avoid using circuit paths if no node in the path supports the ntor
circuit extension handshake. Implements ticket 9777.

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@ -72,6 +72,9 @@ static void pathbias_count_use_failed(origin_circuit_t *circ);
static void pathbias_measure_use_rate(entry_guard_t *guard); static void pathbias_measure_use_rate(entry_guard_t *guard);
static void pathbias_measure_close_rate(entry_guard_t *guard); static void pathbias_measure_close_rate(entry_guard_t *guard);
static void pathbias_scale_use_rates(entry_guard_t *guard); static void pathbias_scale_use_rates(entry_guard_t *guard);
#ifdef CURVE25519_ENABLED
static int circuits_can_use_ntor(void);
#endif
/** This function tries to get a channel to the specified endpoint, /** This function tries to get a channel to the specified endpoint,
* and then calls command_setup_channel() to give it the right * and then calls command_setup_channel() to give it the right
@ -284,21 +287,74 @@ circuit_rep_hist_note_result(origin_circuit_t *circ)
} while (hop!=circ->cpath); } while (hop!=circ->cpath);
} }
#ifdef CURVE25519_ENABLED
/** Return 1 iff at least one node in circ's cpath supports ntor. */
static int
circuit_cpath_supports_ntor(const origin_circuit_t *circ)
{
crypt_path_t *head = circ->cpath, *cpath = circ->cpath;
cpath = head;
do {
if (cpath->extend_info &&
!tor_mem_is_zero(
(const char*)cpath->extend_info->curve25519_onion_key.public_key,
CURVE25519_PUBKEY_LEN))
return 1;
cpath = cpath->next;
} while (cpath != head);
return 0;
}
#else
#define circuit_cpath_supports_ntor(circ) 0
#endif
/** Pick all the entries in our cpath. Stop and return 0 when we're /** Pick all the entries in our cpath. Stop and return 0 when we're
* happy, or return -1 if an error occurs. */ * happy, or return -1 if an error occurs. */
static int static int
onion_populate_cpath(origin_circuit_t *circ) onion_populate_cpath(origin_circuit_t *circ)
{ {
int r; int n_tries = 0;
again: #ifdef CURVE25519_ENABLED
r = onion_extend_cpath(circ); const int using_ntor = circuits_can_use_ntor();
if (r < 0) { #else
log_info(LD_CIRC,"Generating cpath hop failed."); const int using_ntor = 0;
return -1; #endif
#define MAX_POPULATE_ATTEMPTS 32
while (1) {
int r = onion_extend_cpath(circ);
if (r < 0) {
log_info(LD_CIRC,"Generating cpath hop failed.");
return -1;
}
if (r == 1) {
/* This circuit doesn't need/shouldn't be forced to have an ntor hop */
if (circ->build_state->desired_path_len <= 1 || ! using_ntor)
return 0;
/* This circuit has an ntor hop. great! */
if (circuit_cpath_supports_ntor(circ))
return 0;
/* No node in the circuit supports ntor. Have we already tried too many
* times? */
if (++n_tries >= MAX_POPULATE_ATTEMPTS)
break;
/* Clear the path and retry */
circuit_clear_cpath(circ);
}
} }
if (r == 0) log_warn(LD_CIRC, "I tried for %d times, but I couldn't build a %d-hop "
goto again; "circuit with at least one node that supports ntor.",
return 0; /* if r == 1 */ MAX_POPULATE_ATTEMPTS,
circ->build_state->desired_path_len);
return -1;
} }
/** Create and return a new origin circuit. Initialize its purpose and /** Create and return a new origin circuit. Initialize its purpose and
@ -3475,6 +3531,9 @@ onion_next_hop_in_cpath(crypt_path_t *cpath)
/** Choose a suitable next hop in the cpath <b>head_ptr</b>, /** Choose a suitable next hop in the cpath <b>head_ptr</b>,
* based on <b>state</b>. Append the hop info to head_ptr. * based on <b>state</b>. Append the hop info to head_ptr.
*
* Return 1 if the path is complete, 0 if we successfully added a hop,
* and -1 on error.
*/ */
static int static int
onion_extend_cpath(origin_circuit_t *circ) onion_extend_cpath(origin_circuit_t *circ)

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@ -709,7 +709,7 @@ circuit_free_cpath(crypt_path_t *cpath)
if (!cpath) if (!cpath)
return; return;
/* it's a doubly linked list, so we have to notice when we've /* it's a circular list, so we have to notice when we've
* gone through it once. */ * gone through it once. */
while (cpath->next && cpath->next != head) { while (cpath->next && cpath->next != head) {
victim = cpath; victim = cpath;
@ -720,6 +720,14 @@ circuit_free_cpath(crypt_path_t *cpath)
circuit_free_cpath_node(cpath); circuit_free_cpath_node(cpath);
} }
/** Remove all the items in the cpath on <b>circ</b>.*/
void
circuit_clear_cpath(origin_circuit_t *circ)
{
circuit_free_cpath(circ->cpath);
circ->cpath = NULL;
}
/** Release all storage held by circuits. */ /** Release all storage held by circuits. */
void void
circuit_free_all(void) circuit_free_all(void)

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@ -50,6 +50,7 @@ void circuit_mark_all_dirty_circs_as_unusable(void);
void circuit_mark_for_close_(circuit_t *circ, int reason, void circuit_mark_for_close_(circuit_t *circ, int reason,
int line, const char *file); int line, const char *file);
int circuit_get_cpath_len(origin_circuit_t *circ); int circuit_get_cpath_len(origin_circuit_t *circ);
void circuit_clear_cpath(origin_circuit_t *circ);
crypt_path_t *circuit_get_cpath_hop(origin_circuit_t *circ, int hopnum); crypt_path_t *circuit_get_cpath_hop(origin_circuit_t *circ, int hopnum);
void circuit_get_all_pending_on_channel(smartlist_t *out, void circuit_get_all_pending_on_channel(smartlist_t *out,
channel_t *chan); channel_t *chan);