metrics: Add a `reason` label to the HS error metrics.

This adds a `reason` label to the `hs_intro_rejected_intro_req_count` and
`hs_rdv_error_count` metrics introduced in #40755.

Metric look up and intialization is now more a bit more involved. This may be
fine for now, but it will become unwieldy if/when we add more labels (and as
such will need to be refactored).

Also, in the future, we may want to introduce finer grained `reason` labels.
For example, the `invalid_introduce2` label actually covers multiple types of
errors that can happen during the processing of an INTRODUCE2 cell (such as
cell parse errors, replays, decryption errors).

Signed-off-by: Gabriela Moldovan <gabi@torproject.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/core/or/circuituse.c b/src/core/or/circuituse.c
index 421d3662af..77c5deaafb 100644
--- a/src/core/or/circuituse.c
+++ b/src/core/or/circuituse.c
@@ -1753,7 +1753,8 @@ circuit_build_failed(origin_circuit_t *circ)
 
     /* If the path failed on an RP, retry it. */
     if (TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) {
-      hs_metrics_failed_rdv(&circ->hs_ident->identity_pk);
+      hs_metrics_failed_rdv(&circ->hs_ident->identity_pk,
+                            HS_METRICS_ERR_RDV_PATH);
       hs_circ_retry_service_rendezvous_point(circ);
     }
 
@@ -1866,7 +1867,8 @@ circuit_build_failed(origin_circuit_t *circ)
                escaped(build_state_get_exit_nickname(circ->build_state)),
                failed_at_last_hop?"last":"non-last");
 
-      hs_metrics_failed_rdv(&circ->hs_ident->identity_pk);
+      hs_metrics_failed_rdv(&circ->hs_ident->identity_pk,
+                            HS_METRICS_ERR_RDV_RP_CONN_FAILURE);
       hs_circ_retry_service_rendezvous_point(circ);
       break;
     /* default: