smart-reboot: add network-idle aware scheduled reboot utility

Add smart-reboot, a lightweight OpenWrt utility that performs
scheduled reboot during a dawn time window when network traffic is idle.

- UCI-based configuration (/etc/config/smart-reboot)
- Procd-managed uloop background daemon
- Dawn time window with periodic retry on active traffic
- Atomic /proc/net/dev telemetry and dynamic ubus L3 device resolution
- Failsafe guards (NTP sync, system uptime, and single daily reboot)

Signed-off-by: Min Choi <3387910@naver.com>

Author: minicom365

utils/smart-reboot/Makefile

@@ -0,0 +1,43 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=smart-reboot
+PKG_VERSION:=1
+PKG_RELEASE:=1
+
+PKG_MAINTAINER:=Min Choi <3387910@naver.com>
+PKG_LICENSE:=GPL-2.0-only
+PKG_LICENSE_FILES:=LICENSE
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/smart-reboot
+  SECTION:=utils
+  CATEGORY:=Utilities
+  TITLE:=Smart reboot based on network idle state
+  DEPENDS:=+ucode +ucode-mod-uci +ucode-mod-log +ucode-mod-fs +ucode-mod-ubus +ucode-mod-uloop
+  PKGARCH:=all
+endef
+
+define Package/smart-reboot/description
+  Reboot router at configured dawn time window only when monitored interfaces are idle.
+endef
+
+define Package/smart-reboot/conffiles
+/etc/config/smart-reboot
+endef
+
+define Build/Compile
+endef
+
+define Package/smart-reboot/install
+	$(INSTALL_DIR) $(1)/etc/config
+	$(INSTALL_CONF) ./files/smart-reboot.config $(1)/etc/config/smart-reboot
+
+	$(INSTALL_DIR) $(1)/etc/init.d
+	$(INSTALL_BIN) ./files/smart-reboot.init $(1)/etc/init.d/smart-reboot
+
+	$(INSTALL_DIR) $(1)/usr/sbin
+	$(INSTALL_BIN) ./files/smart-reboot.uc $(1)/usr/sbin/smart-reboot
+endef
+
+$(eval $(call BuildPackage,smart-reboot))

utils/smart-reboot/files/smart-reboot.config

@@ -0,0 +1,8 @@
+config settings 'settings'
+	option enabled '0'
+	option window_start '03:00'
+	option window_end '06:00'
+	option check_interval '300'
+	option sample_seconds '60'
+	option threshold_kb '256'
+	option last_auto_reboot ''

utils/smart-reboot/files/smart-reboot.init

@@ -0,0 +1,26 @@
+#!/bin/sh /etc/rc.common
+
+START=95
+STOP=10
+USE_PROCD=1
+
+PROG="/usr/sbin/smart-reboot"
+
+start_service() {
+	config_load smart-reboot
+	local enabled
+	config_get enabled settings enabled '0'
+	[ "$enabled" = "1" ] || return 0
+
+	procd_open_instance "smart-reboot"
+	procd_set_param command "$PROG"
+	procd_set_param respawn 3600 5 0
+	procd_set_param stdout 1
+	procd_set_param stderr 1
+	procd_set_param pidfile /var/run/smart-reboot.pid
+	procd_close_instance
+}
+
+service_triggers() {
+	procd_add_reload_trigger "smart-reboot"
+}