1 files changed, 109 insertions, 32 deletions

diff --git a/src/or/microdesc.c b/src/or/microdesc.c
index a81dc54628..b4a934e095 100644
--- a/src/or/microdesc.c
+++ b/src/or/microdesc.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009-2016, The Tor Project, Inc. */
+/* Copyright (c) 2009-2017, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
 /**
@@ -74,6 +74,102 @@ HT_GENERATE2(microdesc_map, microdesc_t, node,
              microdesc_hash_, microdesc_eq_, 0.6,
              tor_reallocarray_, tor_free_)
 
+/************************* md fetch fail cache *****************************/
+
+/* If we end up with too many outdated dirservers, something probably went
+ * wrong so clean up the list. */
+#define TOO_MANY_OUTDATED_DIRSERVERS 30
+
+/** List of dirservers with outdated microdesc information. The smartlist is
+ *  filled with the hex digests of outdated dirservers. */
+static smartlist_t *outdated_dirserver_list = NULL;
+
+/** Note that we failed to fetch a microdescriptor from the relay with
+ *  <b>relay_digest</b> (of size DIGEST_LEN). */
+void
+microdesc_note_outdated_dirserver(const char *relay_digest)
+{
+  char relay_hexdigest[HEX_DIGEST_LEN+1];
+
+  /* Don't register outdated dirservers if we don't have a live consensus,
+   * since we might be trying to fetch microdescriptors that are not even
+   * currently active. */
+  if (!networkstatus_get_live_consensus(approx_time())) {
+    return;
+  }
+
+  if (!outdated_dirserver_list) {
+    outdated_dirserver_list = smartlist_new();
+  }
+
+  tor_assert(outdated_dirserver_list);
+
+  /* If the list grows too big, clean it up */
+  if (BUG(smartlist_len(outdated_dirserver_list) >
+          TOO_MANY_OUTDATED_DIRSERVERS)) {
+    microdesc_reset_outdated_dirservers_list();
+  }
+
+  /* Turn the binary relay digest to a hex since smartlists have better support
+   * for strings than digests. */
+  base16_encode(relay_hexdigest,sizeof(relay_hexdigest),
+                relay_digest, DIGEST_LEN);
+
+  /* Make sure we don't add a dirauth as an outdated dirserver */
+  if (router_get_trusteddirserver_by_digest(relay_digest)) {
+    log_info(LD_GENERAL, "Auth %s gave us outdated dirinfo.", relay_hexdigest);
+    return;
+  }
+
+  /* Don't double-add outdated dirservers */
+  if (smartlist_contains_string(outdated_dirserver_list, relay_hexdigest)) {
+    return;
+  }
+
+  /* Add it to the list of outdated dirservers */
+  smartlist_add_strdup(outdated_dirserver_list, relay_hexdigest);
+
+  log_info(LD_GENERAL, "Noted %s as outdated md dirserver", relay_hexdigest);
+}
+
+/** Return True if the relay with <b>relay_digest</b> (size DIGEST_LEN) is an
+ *  outdated dirserver */
+int
+microdesc_relay_is_outdated_dirserver(const char *relay_digest)
+{
+  char relay_hexdigest[HEX_DIGEST_LEN+1];
+
+  if (!outdated_dirserver_list) {
+    return 0;
+  }
+
+  /* Convert identity digest to hex digest */
+  base16_encode(relay_hexdigest, sizeof(relay_hexdigest),
+                relay_digest, DIGEST_LEN);
+
+  /* Last time we tried to fetch microdescs, was this directory mirror missing
+   * any mds we asked for? */
+  if (smartlist_contains_string(outdated_dirserver_list, relay_hexdigest)) {
+    return 1;
+  }
+
+  return 0;
+}
+
+/** Reset the list of outdated dirservers. */
+void
+microdesc_reset_outdated_dirservers_list(void)
+{
+  if (!outdated_dirserver_list) {
+    return;
+  }
+
+  SMARTLIST_FOREACH(outdated_dirserver_list, char *, cp, tor_free(cp));
+  smartlist_clear(outdated_dirserver_list);
+}
+
+/****************************************************************************/
+
 /** Write the body of <b>md</b> into <b>f</b>, with appropriate annotations.
  * On success, return the total number of bytes written, and set
  * *<b>annotation_len_out</b> to the number of bytes written as
@@ -142,8 +238,8 @@ get_microdesc_cache_noload(void)
   if (PREDICT_UNLIKELY(the_microdesc_cache==NULL)) {
     microdesc_cache_t *cache = tor_malloc_zero(sizeof(*cache));
     HT_INIT(microdesc_map, &cache->map);
-    cache->cache_fname = get_datadir_fname("cached-microdescs");
-    cache->journal_fname = get_datadir_fname("cached-microdescs.new");
+    cache->cache_fname = get_cachedir_fname("cached-microdescs");
+    cache->journal_fname = get_cachedir_fname("cached-microdescs.new");
     the_microdesc_cache = cache;
   }
   return the_microdesc_cache;
@@ -789,6 +885,11 @@ microdesc_free_all(void)
     tor_free(the_microdesc_cache->journal_fname);
     tor_free(the_microdesc_cache);
   }
+
+  if (outdated_dirserver_list) {
+    SMARTLIST_FOREACH(outdated_dirserver_list, char *, cp, tor_free(cp));
+    smartlist_free(outdated_dirserver_list);
+  }
 }
 
 /** If there is a microdescriptor in <b>cache</b> whose sha256 digest is
@@ -804,18 +905,6 @@ microdesc_cache_lookup_by_digest256(microdesc_cache_t *cache, const char *d)
   return md;
 }
 
-/** Return the mean size of decriptors added to <b>cache</b> since it was last
- * cleared.  Used to estimate the size of large downloads. */
-size_t
-microdesc_average_size(microdesc_cache_t *cache)
-{
-  if (!cache)
-    cache = get_microdesc_cache();
-  if (!cache->n_seen)
-    return 512;
-  return (size_t)(cache->total_len_seen / cache->n_seen);
-}
-
 /** Return a smartlist of all the sha256 digest of the microdescriptors that
  * are listed in <b>ns</b> but not present in <b>cache</b>. Returns pointers
  * to internals of <b>ns</b>; you should not free the members of the resulting
@@ -831,8 +920,7 @@ microdesc_list_missing_digest256(networkstatus_t *ns, microdesc_cache_t *cache,
     if (microdesc_cache_lookup_by_digest256(cache, rs->descriptor_digest))
       continue;
     if (downloadable_only &&
-        !download_status_is_ready(&rs->dl_status, now,
-                  get_options()->TestingMicrodescMaxDownloadTries))
+        !download_status_is_ready(&rs->dl_status, now))
       continue;
     if (skip && digest256map_get(skip, (const uint8_t*)rs->descriptor_digest))
       continue;
@@ -888,7 +976,7 @@ update_microdesc_downloads(time_t now)
   smartlist_free(missing);
 }
 
-/** For every microdescriptor listed in the current microdecriptor consensus,
+/** For every microdescriptor listed in the current microdescriptor consensus,
  * update its last_listed field to be at least as recent as the publication
  * time of the current microdescriptor consensus.
  */
@@ -917,20 +1005,9 @@ update_microdescs_from_networkstatus(time_t now)
 int
 we_use_microdescriptors_for_circuits(const or_options_t *options)
 {
-  int ret = options->UseMicrodescriptors;
-  if (ret == -1) {
-    /* UseMicrodescriptors is "auto"; we need to decide: */
-    /* If we are configured to use bridges and none of our bridges
-     * know what a microdescriptor is, the answer is no. */
-    if (options->UseBridges && !any_bridge_supports_microdescriptors())
-      return 0;
-    /* Otherwise, we decide that we'll use microdescriptors iff we are
-     * not a server, and we're not autofetching everything. */
-    /* XXXX++ what does not being a server have to do with it? also there's
-     * a partitioning issue here where bridges differ from clients. */
-    ret = !server_mode(options) && !options->FetchUselessDescriptors;
-  }
-  return ret;
+  if (options->UseMicrodescriptors == 0)
+    return 0; /* the user explicitly picked no */
+  return 1; /* yes and auto both mean yes */
 }
 
 /** Return true iff we should try to download microdescriptors at all. */