hs: Trigger control event when client can't pick HSDir

Inform the control port with an HS_DESC failed event when the client is unable
to pick an HSDir. It's followed by an empty HS_DESC_CONTENT event. In order to
achieve that, some control port code had to be modified to accept a NULL HSDir
identity digest.

This commit also adds a trigger of a failed event when we are unable to
base64-decode the descriptor cookie.

Fixes #22042

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

1 files changed, 6 insertions, 0 deletions

diff --git a/src/or/rendclient.c b/src/or/rendclient.c
index 8d2ae03c9e..88bd5cd39e 100644
--- a/src/or/rendclient.c
+++ b/src/or/rendclient.c
@@ -724,6 +724,9 @@ directory_get_from_hs_dir(const char *desc_id,
     hs_dir = pick_hsdir(desc_id, desc_id_base32);
     if (!hs_dir) {
       /* No suitable hs dir can be found, stop right now. */
+      control_event_hs_descriptor_failed(rend_query, NULL, "QUERY_NO_HSDIR");
+      control_event_hs_descriptor_content(rend_data_get_address(rend_query),
+                                          desc_id_base32, NULL, NULL);
       return 0;
     }
   }
@@ -744,6 +747,9 @@ directory_get_from_hs_dir(const char *desc_id,
                       REND_DESC_COOKIE_LEN,
                       0)<0) {
       log_warn(LD_BUG, "Could not base64-encode descriptor cookie.");
+      control_event_hs_descriptor_failed(rend_query, hsdir_fp, "BAD_DESC");
+      control_event_hs_descriptor_content(rend_data_get_address(rend_query),
+                                          desc_id_base32, hsdir_fp, NULL);
       return 0;
     }
     /* Remove == signs. */