ffho-salt-public/systemd/wait-for-routes

#!/bin/sh
#
# Wait for routing adjacencies to come up and produce a default route
#
# Maximilian Wilhelm <max@sdn.clinic>
#  -- Mon, 05 Apr 2021 02:31:58 +0200

# Wait for this amount of seconds before giving up
timeout=30

# Wait for IPv4 default route to emerge
(
	for n in $(seq 1 $timeout); do
		# If there is an IPv4 default route, stop waiting
		if ip -4 route | grep -q "^default"; then
			break
		fi

		sleep 1
	done
)&

# Wait for IPv6 default route to emerge
(
	for n in $(seq 1 $timeout); do
		# If there is an IPv6 default route, stop waiting
		if ip -6 route | grep -q "^default"; then
			break
		fi

		sleep 1
	done
)&

# Wait for IPv6 IPs do leave tentative state
# This will most likely be only relevant for nodes with static IPs/route
(
	for n in $(seq 1 $timeout); do
		# If there is an IPv6 in state tentative, wait on
		if ip -6 addr | grep -q "tentative"; then
			sleep 1
		else
			break
		fi
	done

)&

# WAit for both sub-shells to finish
wait

exit 0