Provide generic mechanism for scheduler to query writeable cells on a channel

1 files changed, 6 insertions, 1 deletions

diff --git a/src/or/channel.h b/src/or/channel.h
index 148199235a..28b5ab0ccf 100644
--- a/src/or/channel.h
+++ b/src/or/channel.h
@@ -110,7 +110,9 @@ struct channel_s {
   int (*matches_extend_info)(channel_t *, extend_info_t *);
   /** Check if this channel matches a target address when extending */
   int (*matches_target)(channel_t *, const tor_addr_t *);
-  /** Write a cell to an open channel */
+  /* Ask the lower layer how many cells can be written */
+  int (*num_cells_writeable)(channel_t *);
+  /* Write a cell to an open channel */
   int (*write_cell)(channel_t *, cell_t *);
   /** Write a packed cell to an open channel */
   int (*write_packed_cell)(channel_t *, packed_cell_t *);
@@ -465,6 +467,9 @@ void channel_listener_dump_statistics(channel_listener_t *chan_l,
 void channel_listener_dump_transport_statistics(channel_listener_t *chan_l,
                                                 int severity);
 
+/* Flow control queries */
+int channel_num_cells_writeable(channel_t *chan);
+
 /* Timestamp queries */
 time_t channel_when_created(channel_t *chan);
 time_t channel_when_last_active(channel_t *chan);