Backport fix for bug 997.

Backporting 6a32beb and ca8708a.

ChangeLog

@@ -27,6 +27,14 @@ Changes in version 0.2.1.16-?? - 2009-??-??
     - Avoid crashing when we have a policy specified in a DirPolicy or
       SocksPolicy or ReachableAddresses option with ports set on it, and we
       re-load the policy.  May fix bug 996.
+    - Hidden service clients didn't use a cached service descriptor that
+      was older than 15 minutes, but wouldn't fetch a new one either. Now,
+      use a cached descriptor no matter how old it is and only fetch a new
+      one when all introduction points fail. Fix for bug 997. Patch from
+      Marcus Griep.
+    - Fix refetching of hidden service descriptors when all introduction
+      points have turned out to not work. Fixes more of bug 997.
+
 
   o Minor bugfixes (on 0.2.1.x):
     - When switching back and forth between bridge mode, do not start

src/or/connection_edge.c

@@ -1683,27 +1683,12 @@ connection_ap_handshake_rewrite_and_attach(edge_connection_t *conn,
       if (conn->rend_data->auth_type == REND_NO_AUTH)
         rend_client_refetch_renddesc(conn->rend_data->onion_address);
     } else { /* r > 0 */
-/** How long after we receive a hidden service descriptor do we consider
- * it valid? */
-#define NUM_SECONDS_BEFORE_HS_REFETCH (60*15)
-      if (now - entry->received < NUM_SECONDS_BEFORE_HS_REFETCH) {
-        conn->_base.state = AP_CONN_STATE_CIRCUIT_WAIT;
-        log_info(LD_REND, "Descriptor is here and fresh enough. Great.");
-        if (connection_ap_handshake_attach_circuit(conn) < 0) {
-          if (!conn->_base.marked_for_close)
-            connection_mark_unattached_ap(conn, END_STREAM_REASON_CANT_ATTACH);
-          return -1;
-        }
-      } else {
-        conn->_base.state = AP_CONN_STATE_RENDDESC_WAIT;
-        log_info(LD_REND, "Stale descriptor %s. Re-fetching.",
-                 safe_str(conn->rend_data->onion_address));
-        /* Fetch both, v0 and v2 rend descriptors in parallel. Use whichever
-         * arrives first. Exception: When using client authorization, only
-         * fetch v2 descriptors.*/
-        rend_client_refetch_v2_renddesc(conn->rend_data);
-        if (conn->rend_data->auth_type == REND_NO_AUTH)
-          rend_client_refetch_renddesc(conn->rend_data->onion_address);
+      conn->_base.state = AP_CONN_STATE_CIRCUIT_WAIT;
+      log_info(LD_REND, "Descriptor is here and fresh enough. Great.");
+      if (connection_ap_handshake_attach_circuit(conn) < 0) {
+        if (!conn->_base.marked_for_close)
+          connection_mark_unattached_ap(conn, END_STREAM_REASON_CANT_ATTACH);
+        return -1;
       }
     }
     return 0;

src/or/rendclient.c

@@ -473,10 +473,9 @@ rend_client_refetch_renddesc(const char *query)
   }
 }
 
-/** Start a connection to a hidden service directory to fetch a v2
- * rendezvous service descriptor for the base32-encoded service ID
- * <b>query</b>.
- */
+/** Unless we already have a descriptor for <b>rend_query</b> with at least
+ * one (possibly) working introduction point in it, start a connection to a
+ * hidden service directory to fetch a v2 rendezvous service descriptor. */
 void
 rend_client_refetch_v2_renddesc(const rend_data_t *rend_query)
 {

src/or/rendcommon.c

@@ -966,6 +966,11 @@ rend_cache_lookup_entry(const char *query, int version, rend_cache_entry_t **e)
   }
   if (!*e)
     return 0;
+  tor_assert((*e)->parsed && (*e)->parsed->intro_nodes);
+  /* XXX022 hack for now, to return "not found" if there are no intro
+   * points remaining. See bug 997. */
+  if (smartlist_len((*e)->parsed->intro_nodes) == 0)
+    return 0;
   return 1;
 }