[tor-commits] [tor/master] Faster circuit_get_by_rend_token_and_purpose()
nickm at torproject.org
nickm at torproject.org
Tue Apr 8 16:07:49 UTC 2014
commit 8b9a2cb68b290e550695124d7ef0511225b451d5
Author: Nick Mathewson <nickm at torproject.org>
Date: Fri Sep 27 11:54:36 2013 -0400
Faster circuit_get_by_rend_token_and_purpose()
On busy servers, this function takes up something like 3-7% in
different profiles, and gets invoked every time we need to participate
as the midpoint in a hidden service.
So maybe walking through a linked list of all the circuits here wasn't
a good idea.
---
changes/bug9841 | 7 +++
src/or/circuitlist.c | 148 +++++++++++++++++++++++++++++++++++++++++++++-----
src/or/circuitlist.h | 2 +
src/or/or.h | 34 +++++++-----
src/or/rendmid.c | 6 +-
5 files changed, 166 insertions(+), 31 deletions(-)
diff --git a/changes/bug9841 b/changes/bug9841
new file mode 100644
index 0000000..8b40dda0
--- /dev/null
+++ b/changes/bug9841
@@ -0,0 +1,7 @@
+ o Minor features (performance):
+
+ - Faster server-side lookups of rendezvous and introduction point
+ circuits by using hashtables instead of linear searches over all
+ the circuits. These functions previously accounted between 3 and
+ 7% of CPU usage on some busy relays.
+
diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c
index b0e24a5..8ab673c 100644
--- a/src/or/circuitlist.c
+++ b/src/or/circuitlist.c
@@ -31,6 +31,7 @@
#include "rephist.h"
#include "routerlist.h"
#include "routerset.h"
+
#include "ht.h"
/********* START VARIABLES **********/
@@ -45,6 +46,9 @@ static void circuit_free(circuit_t *circ);
static void circuit_free_cpath(crypt_path_t *cpath);
static void circuit_free_cpath_node(crypt_path_t *victim);
static void cpath_ref_decref(crypt_path_reference_t *cpath_ref);
+//static void circuit_set_rend_token(or_circuit_t *circ, int is_rend_circ,
+// const uint8_t *token);
+static void circuit_clear_rend_token(or_circuit_t *circ);
/********* END VARIABLES ************/
@@ -672,6 +676,8 @@ circuit_free(circuit_t *circ)
crypto_cipher_free(ocirc->n_crypto);
crypto_digest_free(ocirc->n_digest);
+ circuit_clear_rend_token(ocirc);
+
if (ocirc->rend_splice) {
or_circuit_t *other = ocirc->rend_splice;
tor_assert(other->base_.magic == OR_CIRCUIT_MAGIC);
@@ -1129,21 +1135,118 @@ circuit_get_next_by_pk_and_purpose(origin_circuit_t *start,
return NULL;
}
-/** Return the first OR circuit in the global list whose purpose is
- * <b>purpose</b>, and whose rend_token is the <b>len</b>-byte
- * <b>token</b>. */
+/** Map from rendezvous cookie to or_circuit_t */
+static digestmap_t *rend_cookie_map = NULL;
+
+/** Map from introduction point digest to or_circuit_t */
+static digestmap_t *intro_digest_map = NULL;
+
+/** Return the OR circuit whose purpose is <b>purpose</b>, and whose
+ * rend_token is the REND_TOKEN_LEN-byte <b>token</b>. If <b>is_rend_circ</b>,
+ * look for rendezvous point circuits; otherwise look for introduction point
+ * circuits. */
static or_circuit_t *
-circuit_get_by_rend_token_and_purpose(uint8_t purpose, const char *token,
- size_t len)
+circuit_get_by_rend_token_and_purpose(uint8_t purpose, int is_rend_circ,
+ const char *token)
{
- circuit_t *circ;
- for (circ = global_circuitlist; circ; circ = circ->next) {
- if (! circ->marked_for_close &&
- circ->purpose == purpose &&
- tor_memeq(TO_OR_CIRCUIT(circ)->rend_token, token, len))
- return TO_OR_CIRCUIT(circ);
+ or_circuit_t *circ;
+ digestmap_t *map = is_rend_circ ? rend_cookie_map : intro_digest_map;
+
+ if (!map)
+ return NULL;
+
+ circ = digestmap_get(map, token);
+ if (!circ ||
+ circ->base_.purpose != purpose ||
+ circ->base_.marked_for_close)
+ return NULL;
+
+ if (!circ->rendinfo ||
+ ! bool_eq(circ->rendinfo->is_rend_circ, is_rend_circ) ||
+ tor_memneq(circ->rendinfo->rend_token, token, REND_TOKEN_LEN)) {
+ char *t = tor_strdup(hex_str(token, REND_TOKEN_LEN));
+ log_warn(LD_BUG, "Wanted a circuit with %s:%d, but lookup returned %s:%d",
+ safe_str(t), is_rend_circ,
+ safe_str(hex_str(circ->rendinfo->rend_token, REND_TOKEN_LEN)),
+ (int)circ->rendinfo->is_rend_circ);
+ tor_free(t);
+ return NULL;
}
- return NULL;
+
+ return circ;
+}
+
+/** Clear the rendezvous cookie or introduction point key digest that's
+ * configured on <b>circ</b>, if any, and remove it from any such maps. */
+static void
+circuit_clear_rend_token(or_circuit_t *circ)
+{
+ or_circuit_t *found_circ;
+ digestmap_t *map;
+
+ if (!circ || !circ->rendinfo)
+ return;
+
+ map = circ->rendinfo->is_rend_circ ? rend_cookie_map : intro_digest_map;
+
+ if (!map) {
+ log_warn(LD_BUG, "Tried to clear rend token on circuit, but found no map");
+ return;
+ }
+
+ found_circ = digestmap_get(map, circ->rendinfo->rend_token);
+ if (found_circ == circ) {
+ /* Great, this is the right one. */
+ digestmap_remove(map, circ->rendinfo->rend_token);
+ } else if (found_circ) {
+ log_warn(LD_BUG, "Tried to clear rend token on circuit, but "
+ "it was already replaced in the map.");
+ } else {
+ log_warn(LD_BUG, "Tried to clear rend token on circuit, but "
+ "it not in the map at all.");
+ }
+
+ tor_free(circ->rendinfo); /* Sets it to NULL too */
+}
+
+/** Set the rendezvous cookie (if is_rend_circ), or the introduction point
+ * digest (if ! is_rend_circ) of <b>circ</b> to the REND_TOKEN_LEN-byte value
+ * in <b>token</b>, and add it to the appropriate map. If it previously had a
+ * token, clear it. If another circuit previously had the same
+ * cookie/intro-digest, mark that circuit and remove it from the map. */
+static void
+circuit_set_rend_token(or_circuit_t *circ, int is_rend_circ,
+ const uint8_t *token)
+{
+ digestmap_t **map_p, *map;
+ or_circuit_t *found_circ;
+
+ /* Find the right map, creating it as needed */
+ map_p = is_rend_circ ? &rend_cookie_map : &intro_digest_map;
+
+ if (!*map_p)
+ *map_p = digestmap_new();
+
+ map = *map_p;
+
+ /* If this circuit already has a token, we need to remove that. */
+ if (circ->rendinfo)
+ circuit_clear_rend_token(circ);
+
+ found_circ = digestmap_get(map, (const char *)token);
+ if (found_circ) {
+ tor_assert(found_circ != circ);
+ circuit_clear_rend_token(found_circ);
+ if (! found_circ->base_.marked_for_close)
+ circuit_mark_for_close(TO_CIRCUIT(found_circ), END_CIRC_REASON_FINISHED);
+ }
+
+ /* Now set up the rendinfo */
+ circ->rendinfo = tor_malloc(sizeof(*circ->rendinfo));
+ memcpy(circ->rendinfo->rend_token, token, REND_TOKEN_LEN);
+ circ->rendinfo->is_rend_circ = is_rend_circ ? 1 : 0;
+
+ digestmap_set(map, (const char *)token, circ);
}
/** Return the circuit waiting for a rendezvous with the provided cookie.
@@ -1154,7 +1257,7 @@ circuit_get_rendezvous(const char *cookie)
{
return circuit_get_by_rend_token_and_purpose(
CIRCUIT_PURPOSE_REND_POINT_WAITING,
- cookie, REND_COOKIE_LEN);
+ 1, cookie);
}
/** Return the circuit waiting for intro cells of the given digest.
@@ -1164,8 +1267,23 @@ or_circuit_t *
circuit_get_intro_point(const char *digest)
{
return circuit_get_by_rend_token_and_purpose(
- CIRCUIT_PURPOSE_INTRO_POINT, digest,
- DIGEST_LEN);
+ CIRCUIT_PURPOSE_INTRO_POINT, 0, digest);
+}
+
+/** Set the rendezvous cookie of <b>circ</b> to <b>cookie</b>. If another
+ * circuit previously had that cookie, mark it. */
+void
+circuit_set_rendezvous_cookie(or_circuit_t *circ, const uint8_t *cookie)
+{
+ circuit_set_rend_token(circ, 1, cookie);
+}
+
+/** Set the intro point key digest of <b>circ</b> to <b>cookie</b>. If another
+ * circuit previously had that intro point digest, mark it. */
+void
+circuit_set_intro_point_digest(or_circuit_t *circ, const uint8_t *digest)
+{
+ circuit_set_rend_token(circ, 0, digest);
}
/** Return a circuit that is open, is CIRCUIT_PURPOSE_C_GENERAL,
diff --git a/src/or/circuitlist.h b/src/or/circuitlist.h
index 874f68c..d8c107f 100644
--- a/src/or/circuitlist.h
+++ b/src/or/circuitlist.h
@@ -43,6 +43,8 @@ origin_circuit_t *circuit_get_next_by_pk_and_purpose(origin_circuit_t *start,
const char *digest, uint8_t purpose);
or_circuit_t *circuit_get_rendezvous(const char *cookie);
or_circuit_t *circuit_get_intro_point(const char *digest);
+void circuit_set_rendezvous_cookie(or_circuit_t *circ, const uint8_t *cookie);
+void circuit_set_intro_point_digest(or_circuit_t *circ, const uint8_t *digest);
origin_circuit_t *circuit_find_to_cannibalize(uint8_t purpose,
extend_info_t *info, int flags);
void circuit_mark_all_unused_circs(void);
diff --git a/src/or/or.h b/src/or/or.h
index 5318b0f..510b8ea 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -99,6 +99,7 @@
#include "ht.h"
#include "replaycache.h"
#include "crypto_curve25519.h"
+#include "tor_queue.h"
/* These signals are defined to help handle_control_signal work.
*/
@@ -3152,20 +3153,8 @@ typedef struct or_circuit_t {
* is not marked for close. */
struct or_circuit_t *rend_splice;
-#if REND_COOKIE_LEN >= DIGEST_LEN
-#define REND_TOKEN_LEN REND_COOKIE_LEN
-#else
-#define REND_TOKEN_LEN DIGEST_LEN
-#endif
+ struct or_circuit_rendinfo_s *rendinfo;
- /** A hash of location-hidden service's PK if purpose is INTRO_POINT, or a
- * rendezvous cookie if purpose is REND_POINT_WAITING. Filled with zeroes
- * otherwise.
- * ???? move to a subtype or adjunct structure? Wastes 20 bytes. -NM
- */
- char rend_token[REND_TOKEN_LEN];
-
- /* ???? move to a subtype or adjunct structure? Wastes 20 bytes -NM */
/** Stores KH for the handshake. */
char rend_circ_nonce[DIGEST_LEN];/* KH in tor-spec.txt */
@@ -3186,6 +3175,25 @@ typedef struct or_circuit_t {
uint64_t total_cell_waiting_time;
} or_circuit_t;
+typedef struct or_circuit_rendinfo_s {
+
+#if REND_COOKIE_LEN != DIGEST_LEN
+#error "The REND_TOKEN_LEN macro assumes REND_COOKIE_LEN == DIGEST_LEN"
+#endif
+#define REND_TOKEN_LEN DIGEST_LEN
+
+ /** A hash of location-hidden service's PK if purpose is INTRO_POINT, or a
+ * rendezvous cookie if purpose is REND_POINT_WAITING. Filled with zeroes
+ * otherwise.
+ */
+ char rend_token[REND_TOKEN_LEN];
+
+ /** True if this is a rendezvous point circuit; false if this is an
+ * introduction point. */
+ unsigned is_rend_circ;
+
+} or_circuit_rendinfo_t;
+
/** Convert a circuit subtype to a circuit_t. */
#define TO_CIRCUIT(x) (&((x)->base_))
diff --git a/src/or/rendmid.c b/src/or/rendmid.c
index 1bd11f6..8090bf2 100644
--- a/src/or/rendmid.c
+++ b/src/or/rendmid.c
@@ -111,7 +111,7 @@ rend_mid_establish_intro(or_circuit_t *circ, const uint8_t *request,
/* Now, set up this circuit. */
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_INTRO_POINT);
- memcpy(circ->rend_token, pk_digest, DIGEST_LEN);
+ circuit_set_intro_point_digest(circ, (uint8_t *)pk_digest);
log_info(LD_REND,
"Established introduction point on circuit %u for service %s",
@@ -251,7 +251,7 @@ rend_mid_establish_rendezvous(or_circuit_t *circ, const uint8_t *request,
}
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_POINT_WAITING);
- memcpy(circ->rend_token, request, REND_COOKIE_LEN);
+ circuit_set_rendezvous_cookie(circ, request);
base16_encode(hexid,9,(char*)request,4);
@@ -327,7 +327,7 @@ rend_mid_rendezvous(or_circuit_t *circ, const uint8_t *request,
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_ESTABLISHED);
circuit_change_purpose(TO_CIRCUIT(rend_circ),
CIRCUIT_PURPOSE_REND_ESTABLISHED);
- memset(circ->rend_token, 0, REND_COOKIE_LEN);
+ circuit_set_rendezvous_cookie(circ, NULL);
rend_circ->rend_splice = circ;
circ->rend_splice = rend_circ;
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