Commit cbda016b authored by Nick Mathewson's avatar Nick Mathewson 🦀
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Send END cells on bufferevent tunneled directory conns 

Our old code correctly called bufferevent_flush() on linked
connections to make sure that the other side got an EOF event... but
it didn't call bufferevent_flush() when the connection wasn't
hold_open_until_flushed.  Directory connections don't use
hold_open_until_flushed, so the linked exit connection never got an
EOF, so they never sent a RELAY_END cell to the client, and the
client never concluded that data had arrived.

The solution is to make the bufferevent_flush() code apply to _all_
closing linked conns whose partner is not already marked for close.
parent 1c664941

src/or/main.c

+9 −4
Original line number Diff line number Diff line
@@ -231,6 +231,8 @@ connection_add_impl(connection_t *conn, int is_connecting) 
        conn->linked_conn->bufev = pair[1];

      } /* else the other side already was added, and got a bufferevent_pair */

      connection_configure_bufferevent_callbacks(conn);

    } else {

      tor_assert(!conn->linked);

    }



    if (conn->bufev && conn->inbuf) {
@@ -722,14 +724,17 @@ conn_close_if_marked(int i) 
  /* assert_all_pending_dns_resolves_ok(); */



#ifdef USE_BUFFEREVENTS

  if (conn->bufev && conn->hold_open_until_flushed) {

    if (conn->linked) {

  if (conn->bufev) {

    if (conn->hold_open_until_flushed &&

        evbuffer_get_length(bufferevent_get_output(conn->bufev))) {

      /* don't close yet. */

      return 0;

    }

    if (conn->linked_conn && ! conn->linked_conn->marked_for_close) {

      /* We need to do this explicitly so that the linked connection

       * notices that there was an EOF. */

      bufferevent_flush(conn->bufev, EV_WRITE, BEV_FINISHED);

    }

    if (evbuffer_get_length(bufferevent_get_output(conn->bufev)))

      return 0;

  }

#endif