1 files changed, 171 insertions, 0 deletions
diff --git a/src/feature/hs/hs_metrics.c b/src/feature/hs/hs_metrics.c
new file mode 100644
index 0000000000..e6d3084f26
--- /dev/null
+++ b/src/feature/hs/hs_metrics.c
@@ -0,0 +1,171 @@
+/* Copyright (c) 2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file hs_metrics.c
+ * @brief Onion service metrics exposed through the MetricsPort
+ **/
+
+#define HS_METRICS_ENTRY_PRIVATE
+
+#include "orconfig.h"
+
+#include "lib/malloc/malloc.h"
+#include "lib/container/smartlist.h"
+#include "lib/metrics/metrics_store.h"
+
+#include "feature/hs/hs_metrics.h"
+#include "feature/hs/hs_metrics_entry.h"
+#include "feature/hs/hs_service.h"
+
+/** Return a static buffer pointer that contains the port as a string.
+ *
+ * Subsequent call to this function invalidates the previous buffer. */
+static const char *
+port_to_str(const uint16_t port)
+{
+  static char buf[8];
+  tor_snprintf(buf, sizeof(buf), "%u", port);
+  return buf;
+}
+
+/** Return a static buffer pointer that contains a formatted label on the form
+ * of key=value.
+ *
+ * Subsequent call to this function invalidates the previous buffer. */
+static const char *
+format_label(const char *key, const char *value)
+{
+  static char buf[128];
+  tor_snprintf(buf, sizeof(buf), "%s=%s", key, value);
+  return buf;
+}
+
+/** Initialize a metrics store for the given service.
+ *
+ * Essentially, this goes over the base_metrics array and adds them all to the
+ * store set with their label(s) if any. */
+static void
+init_store(hs_service_t *service)
+{
+  metrics_store_t *store;
+
+  tor_assert(service);
+
+  store = service->metrics.store;
+
+  for (size_t i = 0; i < base_metrics_size; ++i) {
+    metrics_store_entry_t *entry =
+      metrics_store_add(store, base_metrics[i].type, base_metrics[i].name,
+                        base_metrics[i].help);
+
+    /* Add labels to the entry. */
+    metrics_store_entry_add_label(entry,
+                        format_label("onion", service->onion_address));
+    if (base_metrics[i].port_as_label && service->config.ports) {
+      SMARTLIST_FOREACH_BEGIN(service->config.ports,
+                              const rend_service_port_config_t *, p) {
+        metrics_store_entry_add_label(entry,
+                      format_label("port", port_to_str(p->virtual_port)));
+      } SMARTLIST_FOREACH_END(p);
+    }
+  }
+}
+
+/** Update the metrics key entry in the store in the given service. The port,
+ * if non 0, is used to find the correct metrics entry. The value n is the
+ * value used to update the entry. */
+void
+hs_metrics_update_by_service(const hs_metrics_key_t key,
+                             hs_service_t *service, const uint16_t port,
+                             int64_t n)
+{
+  tor_assert(service);
+
+  /* Get the metrics entry in the store. */
+  smartlist_t *entries = metrics_store_get_all(service->metrics.store,
+                                               base_metrics[key].name);
+  if (BUG(!entries)) {
+    return;
+  }
+
+  /* We need to find the right metrics entry by finding the port label if any.
+   *
+   * XXX: This is not the most optimal due to the string format. Maybe at some
+   * point turn this into a kvline and a map in a metric entry? */
+  SMARTLIST_FOREACH_BEGIN(entries, metrics_store_entry_t *, entry) {
+    if (port == 0 ||
+        metrics_store_entry_has_label(entry,
+                            format_label("port", port_to_str(port)))) {
+      metrics_store_entry_update(entry, n);
+      break;
+    }
+  } SMARTLIST_FOREACH_END(entry);
+}
+
+/** Update the metrics key entry in the store of a service identified by the
+ * given identity public key. The port, if non 0, is used to find the correct
+ * metrics entry. The value n is the value used to update the entry.
+ *
+ * This is used by callsite that have access to the key but not the service
+ * object so an extra lookup is done to find the service. */
+void
+hs_metrics_update_by_ident(const hs_metrics_key_t key,
+                           const ed25519_public_key_t *ident_pk,
+                           const uint16_t port, int64_t n)
+{
+  hs_service_t *service;
+
+  tor_assert(ident_pk);
+
+  service = hs_service_find(ident_pk);
+  if (!service) {
+    /* This is possible because an onion service client can end up here due to
+     * having an identity key onto a connection _to_ an onion service. We
+     * can't differentiate that from an actual onion service initiated by a
+     * service and thus the only way to know is to lookup the service. */
+    return;
+  }
+  hs_metrics_update_by_service(key, service, port, n);
+}
+
+/** Return a list of all the onion service metrics stores. This is the
+ * function attached to the .get_metrics() member of the subsys_t. */
+const smartlist_t *
+hs_metrics_get_stores(void)
+{
+  /* We can't have the caller to free the returned list so keep it static,
+   * simply update it. */
+  static smartlist_t *stores_list = NULL;
+
+  smartlist_free(stores_list);
+  stores_list = hs_service_get_metrics_stores();
+  return stores_list;
+}
+
+/** Initialize the metrics store in the given service. */
+void
+hs_metrics_service_init(hs_service_t *service)
+{
+  tor_assert(service);
+
+  /* This function is called when we register a service and so it could either
+   * be a new service or a service that was just reloaded through a HUP signal
+   * for instance. Thus, it is possible that the service has already an
+   * initialized store. If so, just return. */
+  if (service->metrics.store) {
+    return;
+  }
+
+  service->metrics.store = metrics_store_new();
+  init_store(service);
+}
+
+/** Free the metrics store in the given service. */
+void
+hs_metrics_service_free(hs_service_t *service)
+{
+  tor_assert(service);
+
+  metrics_store_free(service->metrics.store);
+}