net: mstpd: new package (multiple spanning tree daemon)

This change adds support for mstpd (Multiple Spanning Tree Protocol
Daemon).

mstpd works reasonably well with RSTP.
MSTP protocol works ok, but is known to have some issues with some managed
switches.

In order to get this to work, each physical switch port needs to have it's
own software network interface (so, for example: port 0 <==> eth0). This
means that this is suited mostly for higher end devices that can process
STP packets in software.

An interface for `swconfig` or Linux's DSA or switchdev would haven been
interesting, but it never materialized.

Adding this in the OpenWrt packages feed may provide some interest or
feedback on whether `mstpd` should do more, to integrate with managed
switches and offer some basis for Linux (through OpenWrt) as an OS for
managed switches.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

net/mstpd/Config.in

@@ -0,0 +1,12 @@
+menu "Configuration"
+	depends on PACKAGE_mstpd
+
+config MSTPD_RTNL_RCV_BUFSIZE
+	int "Netlink receive buffer size"
+	default 262144
+
+config MSTPD_RTNL_SND_BUFSIZE
+	int "Netlink send buffer size"
+	default 262144
+
+endmenu

net/mstpd/Makefile

@@ -0,0 +1,58 @@
+#
+# Copyright (C) 2019 Alexandru Ardelean <ardeleanalex@gmail.com>
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=mstpd
+PKG_VERSION:=0.0.8
+PKG_RELEASE:=1
+
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=https://codeload.github.com/mstpd/mstpd/tar.gz/$(PKG_VERSION)?
+PKG_HASH:=dd6492039368efff0bd13b3f9c8bb32d859ebfe258a70ef23b2163c4b6c35f0c
+
+PKG_MAINTAINER:=Alexandru Ardelean <ardeleanalex@gmail.com>
+PKG_LICENSE:=GPL-2.0-or-later
+PKG_LICENSE_FILES:=LICENSE
+
+PKG_FIXUP:=autoreconf
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/mstpd
+  SECTION:=net
+  CATEGORY:=Network
+  TITLE:=Multiple Spanning Tree Protocol daemon
+  URL:=https://github.com/mstpd/mstpd
+endef
+
+define Package/mstpd/description
+  Multiple Spanning Tree Protocol daemon.
+  Implements MSTP which is not implemented yet in the Linux kernel.
+endef
+
+define Package/mstpd/config
+  source "$(SOURCE)/Config.in"
+endef
+
+TARGET_CFLAGS += \
+	-DRTNL_RCV_BUFSIZE=$(CONFIG_MSTPD_RTNL_RCV_BUFSIZE) \
+	-DRTNL_SND_BUFSIZE=$(CONFIG_MSTPD_RTNL_SND_BUFSIZE)
+
+MAKE_VARS+=MODE=prod
+
+define Package/mstpd/install
+	$(INSTALL_DIR) $(1)/usr/sbin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/mstpd $(1)/usr/sbin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/mstpctl $(1)/usr/sbin
+	$(INSTALL_DIR) $(1)/etc/init.d/
+	$(INSTALL_BIN) ./files/etc/init.d/mstpd.init $(1)/etc/init.d/mstpd
+	$(INSTALL_DIR) $(1)/sbin
+	$(INSTALL_BIN) ./files/sbin/bridge-stp $(1)/sbin
+endef
+
+$(eval $(call BuildPackage,mstpd))

net/mstpd/files/etc/init.d/mstpd.init

@@ -0,0 +1,124 @@
+#!/bin/sh /etc/rc.common
+
+# shellcheck disable=SC2034	# foo appears unused. Verify it or export it.
+
+START=25
+STOP=99
+
+MSTPCTL="/usr/sbin/mstpctl"
+MSTPD="/usr/sbin/mstpd"
+
+USE_PROCD=1
+
+mstpd_get_bridges() {
+	"$MSTPCTL" showbridge | grep -v "^ " | cut -d " " -f 1 2>/dev/null
+}
+
+# mstpd log levels 
+#   LOG_LEVEL_NONE  0
+#   LOG_LEVEL_ERROR 1
+#   LOG_LEVEL_INFO  2
+#   LOG_LEVEL_DEBUG 3
+#   LOG_LEVEL_STATE_MACHINE_TRANSITION 4
+#   LOG_LEVEL_MAX   100
+
+config_bridge_port_mstpd() {
+	local config="$1"
+	local index=$2 # FIXME: maybe remove index later
+	local name=$3
+
+	[ -n "$index" -a -n "$name" ] || return 0
+
+	config_get br_index "$config" br_index
+	[ -n "$br_index" ] || return 0
+	[ "$index" = "$br_index" ] || return 0
+
+	config_get port_name "$config" name
+	[ -n "$port_name" ] || return 0
+
+	for opt in bpduguard; do
+		config_get $opt "$config" $opt
+		eval optval=\$$opt
+		[ -z "$optval" ] || "$MSTPCTL" "set$opt" "$name" "$port_name" "$optval"
+	done
+}
+
+config_bridge_mstpd() {
+	local config="$1"
+	local optval=
+	local name=
+	local enable=
+	local mstid=0 #  for the moment, using only MSTID
+
+	config_get index "$config" index
+	[ -n "$index" ] || return 1
+
+	# Get bridge name
+	config_get name "$config" name
+	[ -n "$name" ] || return 0
+
+	config_get enable "$config" enable
+	if [ "$enable" != "1" ] ; then
+		return 0
+	fi
+
+	list_contains MSTPD_PREINSTALLED_BRIDGES "$name" || \
+		"$MSTPCTL" addbridge "$name"
+	# All options here have 'set$opt' equivalent calls in mstpd,
+	#  hence this trick with the loop
+	for opt in maxage fdelay maxhops hello ageing forcevers txholdcount; do
+		config_get $opt "$config" "$opt"
+		eval optval=\$$opt
+		[ -z "$optval" ] || "$MSTPCTL" set$opt "$name" "$optval"
+	done
+	config_get treeprio "$config" treeprio
+	[ -z "$treeprio" ] || $MSTPCTL settreeprio "$name" "$mstid" "$treeprio"
+	config_foreach config_bridge_port_mstpd bridge_port "$index" "$name"
+	CONFIGURED_BRIDGES="$CONFIGURED_BRIDGES $name"
+	export CONFIGURED_BRIDGES
+}
+
+start_service() {
+	procd_open_instance
+	procd_set_param command $MSTPD
+	procd_append_param command -v 2
+	procd_append_param command -d # don't daemonize, procd will handle that for us
+	procd_append_param command -s # print to syslog
+
+	# set auto respawn behavior
+	procd_set_param respawn
+
+	# reload config on respawn
+	procd_open_trigger
+	procd_add_raw_trigger "instance.start" 2000 "/etc/init.d/mstpd" "reload"
+	procd_close_trigger
+
+	procd_close_instance
+}
+
+service_running() {
+	pgrep mstpd >/dev/null 2>&1
+}
+
+reload_service() {
+	if ! running ; then
+		start
+		return
+	fi
+
+	unset CONFIGURED_BRIDGES
+	MSTPD_PREINSTALLED_BRIDGES="$(mstpd_get_bridges)"
+	export MSTPD_PREINSTALLED_BRIDGES
+
+	config_load 'mstpd'
+	config_foreach config_bridge_mstpd bridge
+
+	for bridge in $(mstpd_get_bridges) ; do
+		list_contains CONFIGURED_BRIDGES "$bridge" || \
+			$MSTPCTL delbridge "$bridge"
+	done
+	# return 0 (success) here, otherwise, and endless restart loop will occur from procd
+	# because the last return code may be mstpctl failing
+	return 0
+}
+

net/mstpd/files/sbin/bridge-stp

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# Dummy file ; don't do anything ;
+# Returning success here, tells the kernel to allow
+# a userspace module to handle STP states
+#
+# Meanwhile, procd will start mstpd, and all will be well
+
+exit 0