Better fix for 997.

ChangeLog

@@ -29,6 +29,11 @@ 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,
+      because there was already one in the cache. Now, fetch a v2
+      descriptor unless the same descriptor was added to the cache within
+      the last 15 minutes. Fixes bug 997; reported by Marcus Griep.
 
   o Minor bugfixes (on 0.2.1.x):
     - When switching back and forth between bridge mode, do not start

src/or/connection_edge.c

@@ -1683,9 +1683,6 @@ 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.");

src/or/or.h

@@ -636,6 +636,10 @@ typedef enum {
 /** Length of a binary-encoded rendezvous service ID. */
 #define REND_SERVICE_ID_LEN 10
 
+/** How long after we receive a hidden service descriptor do we consider
+ * it fresh? */
+#define NUM_SECONDS_BEFORE_HS_REFETCH (60*15)
+
 /** Time period for which a v2 descriptor will be valid. */
 #define REND_TIME_PERIOD_V2_DESC_VALIDITY (24*60*60)
 

src/or/rendclient.c

@@ -482,8 +482,9 @@ rend_client_refetch_v2_renddesc(const rend_data_t *rend_query)
 {
   char descriptor_id[DIGEST_LEN];
   int replicas_left_to_try[REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS];
-  int i, tries_left;
+  int i, tries_left, r;
   rend_cache_entry_t *e = NULL;
+  time_t now = time(NULL);
   tor_assert(rend_query);
   /* Are we configured to fetch descriptors? */
   if (!get_options()->FetchHidServDescriptors) {
@@ -492,9 +493,11 @@ rend_client_refetch_v2_renddesc(const rend_data_t *rend_query)
     return;
   }
   /* Before fetching, check if we already have the descriptor here. */
-  if (rend_cache_lookup_entry(rend_query->onion_address, -1, &e) > 0) {
+  r = rend_cache_lookup_entry(rend_query->onion_address, -1, &e);
+  if (r > 0 && now - e->received < NUM_SECONDS_BEFORE_HS_REFETCH) {
     log_info(LD_REND, "We would fetch a v2 rendezvous descriptor, but we "
-                      "already have that descriptor here. Not fetching.");
+                      "already have a fresh copy of that descriptor here. "
+                      "Not fetching.");
     return;
   }
   log_debug(LD_REND, "Fetching v2 rendezvous descriptor for service %s",