Commit 492c512a authored by teor's avatar teor
Browse files

relay: Improve docs on inform_testing_reachability() 

Document race conditions that we'll resolve in 34067 and 34137.

Part of 33222.
parent 504b16fb

src/feature/relay/selftest.c

+20 −3
Original line number Diff line number Diff line
@@ -269,9 +269,12 @@ router_do_reachability_checks(int test_or, int test_dir) 
  }

}



/** We've decided to start our reachability testing. If all

 * is set, log this to the user. Return 1 if we did, or 0 if

 * we chose not to log anything. */

/** If reachability testing is in progress, let the user know that it's

 * happening.

 *

 * If all is set, log a notice-level message. Return 1 if we did, or 0 if

 * we chose not to log anything, because we were unable to test reachability.

 */

int

inform_testing_reachability(void)

{
@@ -279,6 +282,20 @@ inform_testing_reachability(void) 
  char ipv6_or_buf[TOR_ADDRPORT_BUF_LEN];

  char ipv4_dir_buf[TOR_ADDRPORT_BUF_LEN];



  /* There's a race condition here, between:

   *  - tor launching reachability tests,

   *  - any circuits actually completing,

   *  - routerinfo updates, and

   *  - these log messages.

   * In rare cases, we might log the wrong ports, log when we didn't actually

   * start reachability tests, or fail to log after we actually started

   * reachability tests.

   *

   * After we separate the IPv4 and IPv6 reachability flags in #34067, tor

   * will test any IPv6 address that it discovers after launching reachability

   * checks. We'll deal with late disabled IPv6 ORPorts and IPv4 DirPorts, and

   * extra or skipped log messages in #34137.

   */

  const routerinfo_t *me = router_get_my_routerinfo();

  if (!me)

    return 0;