patch from karsten:

Resolved problems with (re-)fetching hidden service descriptors.
Before, v0 descriptors were not fetched at all (fix on 0.2.0.18-alpha),
re-fetching of v2 descriptors did not stop when a v0 descriptor was
received (fix on 0.2.0.18-alpha), and re-fetching of v2 descriptors did
not work in all cases (fix on 0.2.0.19-alpha).


svn:r13540

src/or/connection.c

@@ -2436,11 +2436,13 @@ connection_get_by_type_state(int type, int state)
 
 /** Return a connection of type <b>type</b> that has rendquery equal
  * to <b>rendquery</b>, and that is not marked for close. If state
- * is non-zero, conn must be of that state too.
+ * is non-zero, conn must be of that state too. If rendversion is
+ * nonnegative, conn must fetch that rendversion, too.
  */
 connection_t *
 connection_get_by_type_state_rendquery(int type, int state,
-                                       const char *rendquery)
+                                       const char *rendquery,
+                                       int rendversion)
 {
   smartlist_t *conns = get_connection_array();
 
@@ -2453,6 +2455,8 @@ connection_get_by_type_state_rendquery(int type, int state,
         !conn->marked_for_close &&
         (!state || state == conn->state)) {
       if (type == CONN_TYPE_DIR &&
+          (rendversion < 0 ||
+                  rendversion == TO_DIR_CONN(conn)->rend_version) &&
           !rend_cmp_service_ids(rendquery, TO_DIR_CONN(conn)->rend_query))
         return conn;
       else if (CONN_IS_EDGE(conn) &&

src/or/directory.c

@@ -880,6 +880,7 @@ directory_send_command(dir_connection_t *conn,
       tor_assert(strlen(resource) <= REND_SERVICE_ID_LEN_BASE32);
       /* This breaks the function abstraction. */
       strlcpy(conn->rend_query, resource, sizeof(conn->rend_query));
+      conn->rend_version = 0;
 
       httpcommand = "GET";
       /* Request the most recent versioned descriptor. */
@@ -894,6 +895,7 @@ directory_send_command(dir_connection_t *conn,
       tor_assert(strlen(resource) <= REND_DESC_ID_V2_LEN_BASE32);
       /* Remember the query to refer to it when a response arrives. */
       strlcpy(conn->rend_query, payload, sizeof(conn->rend_query));
+      conn->rend_version = 2;
       payload = NULL;
       httpcommand = "GET";
       len = strlen(resource) + 32;

src/or/or.h

@@ -1053,6 +1053,9 @@ typedef struct dir_connection_t {
   /** The zlib object doing on-the-fly compression for spooled data. */
   tor_zlib_state_t *zlib_state;
 
+  /** What hidden service descriptor are we fetching, if any? */
+  int rend_version;
+
   /** What rendezvous service are we querying for? */
   char rend_query[REND_SERVICE_ID_LEN_BASE32+1];
 
@@ -2751,7 +2754,8 @@ connection_t *connection_get_by_type_addr_port_purpose(int type, uint32_t addr,
                                                    uint16_t port, int purpose);
 connection_t *connection_get_by_type_state(int type, int state);
 connection_t *connection_get_by_type_state_rendquery(int type, int state,
-                                                     const char *rendquery);
+                                                     const char *rendquery,
+                                                     int rendversion);
 
 #define connection_speaks_cells(conn) ((conn)->type == CONN_TYPE_OR)
 int connection_is_listener(connection_t *conn);

src/or/rendclient.c

@@ -401,7 +401,7 @@ rend_client_refetch_renddesc(const char *query)
     return;
   log_info(LD_REND, "Fetching rendezvous descriptor for service %s",
            escaped_safe_str(query));
-  if (connection_get_by_type_state_rendquery(CONN_TYPE_DIR, 0, query)) {
+  if (connection_get_by_type_state_rendquery(CONN_TYPE_DIR, 0, query, 0)) {
     log_info(LD_REND,"Would fetch a new renddesc here (for %s), but one is "
              "already in progress.", escaped_safe_str(query));
   } else {
@@ -421,6 +421,7 @@ rend_client_refetch_v2_renddesc(const char *query)
   char descriptor_id[DIGEST_LEN];
   int replicas_left_to_try[REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS];
   int i, tries_left;
+  rend_cache_entry_t *e = NULL;
   tor_assert(query);
   tor_assert(strlen(query) == REND_SERVICE_ID_LEN_BASE32);
   /* Are we configured to fetch descriptors? */
@@ -429,6 +430,12 @@ rend_client_refetch_v2_renddesc(const char *query)
         "service descriptor, but are not fetching service descriptors.");
     return;
   }
+  /* Before fetching, check if we already have the descriptor here. */
+  if (rend_cache_lookup_entry(query, -1, &e) > 0) {
+    log_info(LD_REND, "We would fetch a v2 rendezvous descriptor, but we "
+                      "already have that descriptor here. Not fetching.");
+    return;
+  }
   log_debug(LD_REND, "Fetching v2 rendezvous descriptor for service %s",
             safe_str(query));
   /* Randomly iterate over the replicas until a descriptor can be fetched
@@ -506,7 +513,7 @@ rend_client_remove_intro_point(extend_info_t *failed_intro, const char *query)
 
     /* move all pending streams back to renddesc_wait */
     while ((conn = connection_get_by_type_state_rendquery(CONN_TYPE_AP,
-                                   AP_CONN_STATE_CIRCUIT_WAIT, query))) {
+                                   AP_CONN_STATE_CIRCUIT_WAIT, query, -1))) {
       conn->state = AP_CONN_STATE_RENDDESC_WAIT;
     }