Add origin circuit event pubsub system

Add a publish-subscribe subsystem to publish messages about changes to
origin circuits.

Functions in circuitbuild.c and circuitlist.c publish messages to this
subsystem.

Move circuit event constants out of control.h so that subscribers
don't have to include all of control.h to take actions based on
messages they receive.

Part of ticket 27167.

1 files changed, 89 insertions, 0 deletions

diff --git a/src/core/or/ocirc_event.h b/src/core/or/ocirc_event.h
new file mode 100644
index 0000000000..19a237d7df
--- /dev/null
+++ b/src/core/or/ocirc_event.h
@@ -0,0 +1,89 @@
+/* Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file ocirc_event.h
+ * \brief Header file for ocirc_event.c
+ **/
+
+#ifndef TOR_OCIRC_EVENT_H
+#define TOR_OCIRC_EVENT_H
+
+#include <stdbool.h>
+
+#include "lib/cc/torint.h"
+
+/** Used to indicate the type of a circuit event passed to the controller.
+ * The various types are defined in control-spec.txt */
+typedef enum circuit_status_event_t {
+  CIRC_EVENT_LAUNCHED = 0,
+  CIRC_EVENT_BUILT    = 1,
+  CIRC_EVENT_EXTENDED = 2,
+  CIRC_EVENT_FAILED   = 3,
+  CIRC_EVENT_CLOSED   = 4,
+} circuit_status_event_t;
+
+/** Message for origin circuit state update */
+typedef struct ocirc_state_msg_t {
+  uint32_t gid;       /**< global ID (only origin circuits have them) */
+  int state;          /**< new circuit state */
+  bool onehop;        /**< one-hop circuit? */
+} ocirc_state_msg_t;
+
+/**
+ * Message when a channel gets associated to a circuit.
+ *
+ * This doesn't always correspond to something in circuitbuild.c
+ * setting the n_chan field in the circuit.  For some reason, if
+ * circuit_handle_first_hop() launches a new circuit, it doesn't set
+ * the n_chan field.
+ */
+typedef struct ocirc_chan_msg_t {
+  uint32_t gid;                 /**< global ID */
+  uint64_t chan;                /**< channel ID */
+  bool onehop;                  /**< one-hop circuit? */
+} ocirc_chan_msg_t;
+
+/**
+ * Message for origin circuit status event
+ *
+ * This contains information that ends up in CIRC control protocol events.
+ */
+typedef struct ocirc_cevent_msg_t {
+  uint32_t gid;                 /**< global ID */
+  int evtype;                   /**< event type */
+  int reason;                   /**< reason */
+  bool onehop;                  /**< one-hop circuit? */
+} ocirc_cevent_msg_t;
+
+/** Discriminant values for origin circuit event message */
+typedef enum ocirc_msgtype_t {
+  OCIRC_MSGTYPE_STATE,
+  OCIRC_MSGTYPE_CHAN,
+  OCIRC_MSGTYPE_CEVENT,
+} ocirc_msgtype_t;
+
+/** Discriminated union for the actual message */
+typedef struct ocirc_event_msg_t {
+  int type;
+  union {
+    ocirc_state_msg_t state;
+    ocirc_chan_msg_t chan;
+    ocirc_cevent_msg_t cevent;
+  } u;
+} ocirc_event_msg_t;
+
+/**
+ * Receiver function pointer for origin circuit subscribers
+ *
+ * This function gets called synchronously by the publisher.
+ **/
+typedef void (*ocirc_event_rcvr_t)(const ocirc_event_msg_t *);
+
+void ocirc_event_subscribe(ocirc_event_rcvr_t fn);
+
+#ifdef OCIRC_EVENT_PRIVATE
+void ocirc_event_publish(const ocirc_event_msg_t *msg);
+#endif
+
+#endif  /* defined(TOR_OCIRC_EVENT_STATE_H) */