prop224: Add the dir purpose HAS_FETCHED

Once a descriptor has been successfully downloaded from an HSDir, we flag the
directory connection to "has fetched descriptor" so the connection subsystem
doesn't trigger a new fetch on success.

Same has DIR_PURPOSE_HAS_FETCHED_RENDDESC_V2 but for prop224.

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/or/directory.c

@@ -184,6 +184,7 @@ purpose_needs_anonymity(uint8_t dir_purpose, uint8_t router_purpose,
     case DIR_PURPOSE_FETCH_EXTRAINFO:
     case DIR_PURPOSE_FETCH_MICRODESC:
       return 0;
+    case DIR_PURPOSE_HAS_FETCHED_HSDESC:
     case DIR_PURPOSE_HAS_FETCHED_RENDDESC_V2:
     case DIR_PURPOSE_UPLOAD_RENDDESC_V2:
     case DIR_PURPOSE_FETCH_RENDDESC_V2:
@@ -1126,6 +1127,7 @@ directory_request_new(uint8_t dir_purpose)
   tor_assert(dir_purpose <= DIR_PURPOSE_MAX_);
   tor_assert(dir_purpose != DIR_PURPOSE_SERVER);
   tor_assert(dir_purpose != DIR_PURPOSE_HAS_FETCHED_RENDDESC_V2);
+  tor_assert(dir_purpose != DIR_PURPOSE_HAS_FETCHED_HSDESC);
 
   directory_request_t *result = tor_malloc_zero(sizeof(*result));
   tor_addr_make_null(&result->or_addr_port.addr, AF_INET);
@@ -3110,6 +3112,7 @@ handle_response_fetch_hsdesc_v3(dir_connection_t *conn,
       log_warn(LD_REND, "Failed to store hidden service descriptor");
     } else {
       log_info(LD_REND, "Stored hidden service descriptor successfully.");
+      TO_CONN(conn)->purpose = DIR_PURPOSE_HAS_FETCHED_HSDESC;
     }
     break;
   case 404:
@@ -3409,10 +3412,10 @@ refetch_hsdesc_if_needed(dir_connection_t *dir_conn)
 {
   connection_t *conn = TO_CONN(dir_conn);
 
-  /* If we were trying to fetch a v2 rend desc and did not succeed,
-   * retry as needed. (If a fetch is successful, the connection state
-   * is changed to DIR_PURPOSE_HAS_FETCHED_RENDDESC_V2 to mark that
-   * refetching is unnecessary.) */
+  /* If we were trying to fetch a v2 rend desc and did not succeed, retry as
+   * needed. (If a fetch is successful, the connection state is changed to
+   * DIR_PURPOSE_HAS_FETCHED_RENDDESC_V2 or DIR_PURPOSE_HAS_FETCHED_HSDESC to
+   * mark that refetching is unnecessary.) */
   if (conn->purpose == DIR_PURPOSE_FETCH_RENDDESC_V2 &&
       dir_conn->rend_data &&
       rend_valid_v2_service_id(

src/or/or.h

@@ -425,7 +425,10 @@ typedef enum {
 #define DIR_PURPOSE_UPLOAD_HSDESC 20
 /** A connection to a hidden service directory: fetch a v3 descriptor. */
 #define DIR_PURPOSE_FETCH_HSDESC 21
-#define DIR_PURPOSE_MAX_ 21
+/** A connection to a directory server: set after a hidden service descriptor
+ * is downloaded. */
+#define DIR_PURPOSE_HAS_FETCHED_HSDESC 22
+#define DIR_PURPOSE_MAX_ 22
 
 /** True iff <b>p</b> is a purpose corresponding to uploading
  * data to a directory server. */