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[or-cvs] r17594: {tor} Avoid multiple descriptor-fetch connections to authorities. (in tor/trunk: . src/or)
Author: nickm
Date: 2008-12-11 14:12:55 -0500 (Thu, 11 Dec 2008)
New Revision: 17594
Modified:
tor/trunk/ChangeLog
tor/trunk/src/or/main.c
tor/trunk/src/or/or.h
tor/trunk/src/or/routerlist.c
Log:
Avoid multiple descriptor-fetch connections to authorities. Fixes bug 366.
Modified: tor/trunk/ChangeLog
===================================================================
--- tor/trunk/ChangeLog 2008-12-11 19:12:48 UTC (rev 17593)
+++ tor/trunk/ChangeLog 2008-12-11 19:12:55 UTC (rev 17594)
@@ -16,6 +16,9 @@
dns_inits() every 10 minutes, and change the exit policy to reject *:*
until one succeeds. Fixes bug 691.
- Detect svn revision properly when we're using git-svn.
+ - Try not to open more than one descriptor-downloading connection to an
+ authority at once. This should reduce load on directory authorities.
+ Fixes bug 366.
o Minor features (controller):
- New CONSENSUS_ARRIVED event to note when a new consensus has
Modified: tor/trunk/src/or/main.c
===================================================================
--- tor/trunk/src/or/main.c 2008-12-11 19:12:48 UTC (rev 17593)
+++ tor/trunk/src/or/main.c 2008-12-11 19:12:55 UTC (rev 17594)
@@ -651,6 +651,9 @@
update_router_descriptor_downloads(now);
return;
} else {
+ if (directory_fetches_from_authorities(options))
+ update_router_descriptor_downloads(now);
+
/* if we have enough dir info, then update our guard status with
* whatever we just learned. */
entry_guards_compute_status();
Modified: tor/trunk/src/or/or.h
===================================================================
--- tor/trunk/src/or/or.h 2008-12-11 19:12:48 UTC (rev 17593)
+++ tor/trunk/src/or/or.h 2008-12-11 19:12:55 UTC (rev 17594)
@@ -4207,9 +4207,16 @@
#define PDS_IGNORE_FASCISTFIREWALL (1<<2)
/** Flag to indicate that we should not use any directory authority to which
* we have an existing directory connection for downloading server descriptors
- * or extrainfo documents. [NOTE: Only implemented for
- * router_pick_trusteddirserver, not router_pick_directory_server.]
- * Passed to router_pick_directory_server (et al).*/
+ * or extrainfo documents.
+ *
+ * Passed to router_pick_directory_server (et al)
+ *
+ * [XXXX021 NOTE: This option is only implemented for pick_trusteddirserver,
+ * not pick_directory_server. If we make it work on pick_directory_server
+ * too, we could conservatively make it only prevent multiple fetches to
+ * the same authority, or we could aggressively make it prevent multiple
+ * fetches to _any_ directory server.]
+ */
#define PDS_NO_EXISTING_SERVERDESC_FETCH (1<<3)
#define _PDS_PREFER_TUNNELED_DIR_CONNS (1<<16)
routerstatus_t *router_pick_directory_server(authority_type_t type, int flags);
Modified: tor/trunk/src/or/routerlist.c
===================================================================
--- tor/trunk/src/or/routerlist.c 2008-12-11 19:12:48 UTC (rev 17593)
+++ tor/trunk/src/or/routerlist.c 2008-12-11 19:12:55 UTC (rev 17594)
@@ -3802,7 +3802,7 @@
initiate_descriptor_downloads(routerstatus_t *source,
int purpose,
smartlist_t *digests,
- int lo, int hi)
+ int lo, int hi, int pds_flags)
{
int i, n = hi-lo;
char *resource, *cp;
@@ -3834,7 +3834,7 @@
resource, NULL, 0, 0);
} else {
directory_get_from_dirserver(purpose, ROUTER_PURPOSE_GENERAL, resource,
- PDS_RETRY_IF_NO_SERVERS);
+ pds_flags);
}
tor_free(resource);
}
@@ -3924,6 +3924,22 @@
if (! should_delay && n_downloadable) {
int i, n_per_request;
const char *req_plural = "", *rtr_plural = "";
+ int pds_flags = PDS_RETRY_IF_NO_SERVERS;
+ if (! authdir_mode_any_nonhidserv(options)) {
+ /* If we wind up going to the authorities, we want to only open one
+ * connection to each authority at a time, so that we don't overload
+ * them. We do this by setting PDS_NO_EXISTING_SERVERDESC_FETCH
+ * regardless of whether we're a cache or not; it gets ignored if we're
+ * not calling router_pick_trusteddirserver.
+ *
+ * Setting this flag can make initiate_descriptor_downloads() ignore
+ * requests. We need to make sure that we do in fact call
+ * update_router_descriptor_downloads() later on, once the connections
+ * have succeeded or failed.
+ */
+ pds_flags |= PDS_NO_EXISTING_SERVERDESC_FETCH;
+ }
+
n_per_request = (n_downloadable+MIN_REQUESTS-1) / MIN_REQUESTS;
if (n_per_request > MAX_DL_PER_REQUEST)
n_per_request = MAX_DL_PER_REQUEST;
@@ -3942,7 +3958,8 @@
smartlist_sort_digests(downloadable);
for (i=0; i < n_downloadable; i += n_per_request) {
initiate_descriptor_downloads(NULL, DIR_PURPOSE_FETCH_SERVERDESC,
- downloadable, i, i+n_per_request);
+ downloadable, i, i+n_per_request,
+ pds_flags);
}
last_routerdesc_download_attempted = now;
}
@@ -4068,6 +4085,10 @@
trusted_dir_server_t *ds =
router_get_trusteddirserver_by_digest(ns->identity_digest);
smartlist_t *dl = download_from[i];
+ int pds_flags = PDS_RETRY_IF_NO_SERVERS;
+ if (! authdir_mode_any_nonhidserv(options))
+ pds_flags |= PDS_NO_EXISTING_SERVERDESC_FETCH; /* XXXX021 ignored*/
+
if (!ds) {
log_warn(LD_BUG, "Networkstatus with no corresponding authority!");
continue;
@@ -4079,7 +4100,7 @@
for (j=0; j < smartlist_len(dl); j += MAX_DL_PER_REQUEST) {
initiate_descriptor_downloads(&(ds->fake_status),
DIR_PURPOSE_FETCH_SERVERDESC, dl, j,
- j+MAX_DL_PER_REQUEST);
+ j+MAX_DL_PER_REQUEST, pds_flags);
}
}
@@ -4291,7 +4312,8 @@
smartlist_shuffle(wanted);
for (i = 0; i < smartlist_len(wanted); i += MAX_DL_PER_REQUEST) {
initiate_descriptor_downloads(NULL, DIR_PURPOSE_FETCH_EXTRAINFO,
- wanted, i, i + MAX_DL_PER_REQUEST);
+ wanted, i, i + MAX_DL_PER_REQUEST,
+ PDS_RETRY_IF_NO_SERVERS|PDS_NO_EXISTING_SERVERDESC_FETCH);
}
smartlist_free(wanted);