relay: Remove dirport reachability self test

Regular relays are about to get their DirPort removed so that reachability
test is not useful anymore

Authorities will still use the DirPort but because network reentry towards
their DirPort is now denied network wide, this test is not useful anymore and
so it should simply be considered reachable at all time.

Part of #40282

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

src/feature/dirclient/dirclient.c

@@ -696,24 +696,6 @@ directory_choose_address_routerstatus(const routerstatus_t *status,
   return 0;
 }
 
-/** Return true iff <b>conn</b> is the client side of a directory connection
- * we launched to ourself in order to determine the reachability of our
- * dir_port. */
-static int
-directory_conn_is_self_reachability_test(dir_connection_t *conn)
-{
-  if (conn->requested_resource &&
-      !strcmpstart(conn->requested_resource,"authority")) {
-    const routerinfo_t *me = router_get_my_routerinfo();
-    if (me &&
-        router_digest_is_me(conn->identity_digest) &&
-        tor_addr_eq(&TO_CONN(conn)->addr, &me->ipv4_addr) &&
-        me->ipv4_dirport == conn->base_.port)
-      return 1;
-  }
-  return 0;
-}
-
 /** Called when we are unable to complete the client's request to a directory
  * server due to a network error: Mark the router as down and try again if
  * possible.
@@ -726,9 +708,6 @@ connection_dir_client_request_failed(dir_connection_t *conn)
      * failed. */
     entry_guard_failed(&conn->guard_state);
   }
-  if (directory_conn_is_self_reachability_test(conn)) {
-    return; /* this was a test fetch. don't retry. */
-  }
   if (!entry_list_is_constrained(get_options()))
     router_set_status(conn->identity_digest, 0); /* don't try this one again */
   if (conn->base_.purpose == DIR_PURPOSE_FETCH_SERVERDESC ||
@@ -2516,8 +2495,6 @@ handle_response_fetch_desc(dir_connection_t *conn,
     SMARTLIST_FOREACH(which, char *, cp, tor_free(cp));
     smartlist_free(which);
   }
-  if (directory_conn_is_self_reachability_test(conn))
-    router_dirport_found_reachable();
 
   return 0;
 }