netplugd bridge sync script

my-bridge-ctl.sh

#!/bin/bash

## This script will bounce a br interface if a member interface goes down.
## This will cause router BGP timers to reset, making outages last only seconds instead of minutes.
##
## This script is called by netplug on Vyos:
## /etc/netplug/linkdown.d/my-brdown
##
## Version History
## 1.0 - Initial version
## 1.1 - Add per-interface lockfile
##

LOCKDIR=/var/run/my-bridge-ctl

# Since we only have one br, not going to implement this right now.
#IGNORE_BRIDGES=()

IFACE=$1

#Remove the lock directory
function cleanup {
	# Can't delete directory we are in
	popd > /dev/null

	if rmdir $LOCKDIR; then
		logger -is -t "my-bridge-ctl" -p "kern.info" "Finished"
	else
		logger -is -t "my-bridge-ctl" -p "kern.error" "Failed to remove lock directory '$LOCKDIR'"
		exit 1
	fi
}

# TODO: Make lockdir based on bridge ID to support multiple bridges on one firewall.

if mkdir $LOCKDIR; then
	# We don't want to deal with paths in loops
	pushd $LOCKDIR > /dev/null

	#Ensure that if we "grabbed a lock", we release it
	#Works for SIGTERM and SIGINT(Ctrl-C)
	trap "cleanup" EXIT

	logger -is -t "my-bridge-ctl" -p "kern.info" "Acquired lock, running"

	# Processing starts here

	IFACE_DESC=$(<"/sys/class/net/${IFACE}/ifalias")
	IFACE_BR_DIR="/sys/class/net/${IFACE}/brport"

	if [ ! -d "$IFACE_BR_DIR" ]; then
		logger -is -t "my-bridge-ctl" -p "kern.warning" "Interface ${IFACE} (${IFACE_DESC-no desc}) went down. Not a member of a bridge. Skipping."
	else
		# Make lockfile for our interface
		touch "${IFACE}.starter"

		IFACE_BR_LINK=$(realpath "/sys/class/net/${IFACE}/master")
		IFACE_BR_NAME=$(basename $IFACE_BR_LINK)
		IFACE_BR_DESC=$(<"${IFACE_BR_LINK}/ifalias")
		logger -is -t "my-bridge-ctl" -p "kern.warning" "Interface ${IFACE} (${IFACE_DESC:-no desc}) went down. Member of bridge ${IFACE_BR_NAME} (${IFACE_BR_DESC:-no desc})."

		# TODO: Insert IGNORE_BRIDGE check here

		find "${IFACE_BR_LINK}/brif" -type l -print0 | while IFS= read -r -d $'\0' IFACE_BR_MEMBER_LINK; do
			IFACE_BR_MEMBER_NAME=$(basename $IFACE_BR_MEMBER_LINK)
			IFACE_BR_MEMBER_DESC=$(<"/sys/class/net/${IFACE_BR_MEMBER_NAME}/ifalias")

			if [ "${IFACE}" == "${IFACE_BR_MEMBER_NAME}" ]; then
				logger -is -t "my-bridge-ctl" -p "kern.info" "${IFACE_BR_NAME} caused by ${IFACE_BR_MEMBER_NAME} (${IFACE_BR_MEMBER_DESC}). Skipping."
				continue
			fi

			# Make lockfile for member interfaces
			touch "${IFACE_BR_MEMBER_NAME}.member"
			logger -is -t "my-bridge-ctl" -p "kern.info" "${IFACE_BR_NAME} member interface ${IFACE_BR_MEMBER_NAME} (${IFACE_BR_MEMBER_DESC}). Setting down."

			# Actually bounce link
			ip link set dev ${IFACE_BR_MEMBER_NAME} down

			#logger -is -t "my-bridge-ctl" -p "kern.info" "Interface ${IFACE_BR_MEMBER_NAME} set down."
		done

		# Sleep for a second to let interfaces stabalize
		logger -is -t "my-bridge-ctl" -p "kern.info" "Sleeping 2 seconds."
		sleep 2

		for IFACE_BR_MEMBER_LINK in *.member; do
			IFACE_BR_MEMBER_NAME=${IFACE_BR_MEMBER_LINK%.*}

			# Actually bounce link
			ip link set dev ${IFACE_BR_MEMBER_NAME} up

			# Remove interface lockfile
			rm "${IFACE_BR_MEMBER_LINK}"

			logger -is -t "my-bridge-ctl" -p "kern.info" "Interface ${IFACE_BR_MEMBER_NAME} set up."
		done

		rm "${IFACE}.starter"
	fi

else
	logger -is -t "my-bridge-ctl" -p "kern.info" "Could not create lock directory '$LOCKDIR'"
	exit 1
fi