dos: Add DoS subsystem to manager list

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

src/app/main/subsystem_list.c

@@ -14,6 +14,7 @@
 #include "lib/cc/torint.h"
 
 #include "core/mainloop/mainloop_sys.h"
+#include "core/or/dos_sys.h"
 #include "core/or/or_sys.h"
 #include "feature/control/btrack_sys.h"
 #include "lib/compress/compress_sys.h"
@@ -64,6 +65,7 @@ const subsys_fns_t *tor_subsystems[] = {
 
   &sys_mainloop,
   &sys_or,
+  &sys_dos,
 
   &sys_relay,
   &sys_hs,

src/core/or/dos.h

@@ -9,6 +9,8 @@
 #ifndef TOR_DOS_H
 #define TOR_DOS_H
 
+#include "core/or/or.h"
+
 /* Structure that keeps stats of client connection per-IP. */
 typedef struct cc_client_stats_t {
   /* Number of allocated circuits remaining for this address.  It is

src/core/or/dos_sys.c

@@ -0,0 +1,34 @@
+/* Copyright (c) 2021, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file dos_sys.c
+ * @brief Subsystem definitions for DOS module.
+ **/
+
+#include "lib/subsys/subsys.h"
+
+#include "core/or/dos.h"
+#include "core/or/dos_sys.h"
+
+static int
+subsys_dos_initialize(void)
+{
+  return 0;
+}
+
+static void
+subsys_dos_shutdown(void)
+{
+}
+
+const struct subsys_fns_t sys_dos = {
+  SUBSYS_DECLARE_LOCATION(),
+
+  .name = "dos",
+  .supported = true,
+  .level = DOS_SUBSYS_LEVEL,
+
+  .initialize = subsys_dos_initialize,
+  .shutdown = subsys_dos_shutdown,
+};

src/core/or/dos_sys.h

@@ -0,0 +1,22 @@
+/* Copyright (c) 2021, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file dos_sys.h
+ * @brief Header for core/or/dos_sys.c
+ **/
+
+#ifndef TOR_CORE_OR_DOS_SYS_H
+#define TOR_CORE_OR_DOS_SYS_H
+
+extern const struct subsys_fns_t sys_dos;
+
+/**
+ * Subsystem level for the metrics system.
+ *
+ * Defined here so that it can be shared between the real and stub
+ * definitions.
+ **/
+#define DOS_SUBSYS_LEVEL (21)
+
+#endif /* !defined(TOR_CORE_OR_DOS_SYS_H) */

src/core/or/include.am

@@ -18,6 +18,7 @@ LIBTOR_APP_A_SOURCES += 				\
 	src/core/or/connection_edge.c		\
 	src/core/or/connection_or.c		\
 	src/core/or/dos.c			\
+	src/core/or/dos_sys.c			\
 	src/core/or/extendinfo.c			\
 	src/core/or/onion.c			\
 	src/core/or/ocirc_event.c		\
@@ -64,6 +65,7 @@ noinst_HEADERS +=					\
 	src/core/or/crypt_path_st.h			\
 	src/core/or/destroy_cell_queue_st.h		\
 	src/core/or/dos.h				\
+	src/core/or/dos_sys.h				\
 	src/core/or/edge_connection_st.h		\
 	src/core/or/extendinfo.h			\
 	src/core/or/half_edge_st.h			\