Hash transport instance pointer when using it in event handlers

events.c

@@ -235,7 +235,10 @@ void janus_events_notify_handlers(int type, int subtype, guint64 session_id, ...
 			char *instance = va_arg(args, void *);
 			char id[32];
 			memset(id, 0, sizeof(id));
-			g_snprintf(id, sizeof(id), "%p", instance);
+			/* To avoid sending a stringified version of the transport pointer
+			 * around, we convert it to a number and hash it instead */
+			uint64_t p = janus_uint64_hash(GPOINTER_TO_UINT(instance));
+			g_snprintf(id, sizeof(id), "%"SCNu64, p);
 			json_object_set_new(body, "id", json_string(id));
 			json_t *data = va_arg(args, json_t *);
 			json_object_set_new(body, "data", data);

janus.c

@@ -1051,7 +1051,10 @@ int janus_process_incoming_request(janus_request *request) {
 			json_object_set_new(transport, "transport", json_string(session->source->transport->get_package()));
 			char id[32];
 			memset(id, 0, sizeof(id));
-			g_snprintf(id, sizeof(id), "%p", session->source->instance);
+			/* To avoid sending a stringified version of the transport pointer
+			 * around, we convert it to a number and hash it instead */
+			uint64_t p = janus_uint64_hash(GPOINTER_TO_UINT(session->source->instance));
+			g_snprintf(id, sizeof(id), "%"SCNu64, p);
 			json_object_set_new(transport, "id", json_string(id));
 			janus_events_notify_handlers(JANUS_EVENT_TYPE_SESSION, JANUS_EVENT_SUBTYPE_NONE,
 				session_id, "created", transport);

utils.c

@@ -135,6 +135,13 @@ guint64 *janus_uint64_dup(guint64 num) {
 	return numdup;
 }
 
+guint64 janus_uint64_hash(guint64 num) {
+	num = (num ^ (num >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
+	num = (num ^ (num >> 27)) * UINT64_C(0x94d049bb133111eb);
+	num = num ^ (num >> 31);
+	return num;
+}
+
 int janus_string_to_uint8(const char *str, uint8_t *num) {
 	if(str == NULL || num == NULL)
 		return -EINVAL;

utils.h

@@ -82,6 +82,12 @@ char *janus_random_uuid(void);
  * @returns A pointer to a guint64 number, if successful, NULL otherwise */
 guint64 *janus_uint64_dup(guint64 num);
 
+/*! \brief Helper to hash a guint64 number to another guint64 number
+ * @note We currently only use for event handlers
+ * @param
+ * @returns The hashed number */
+guint64 janus_uint64_hash(guint64 num);
+
 /*! \brief Helper method to convert a string to a uint8_t
  * @note The value of \c num should be ignored, if the method returned an error
  * @param[in] str The string to convert