Hurricane Electric IPv6 Tunnel Broker service

he-ipv6.service

[Unit]
Description=he.net IPv6 tunnel
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
RemainAfterExit=yes
Environment=SERVER_IPV4_ADDR=xxx.xxx.xxx.xxx
Environment=CLIENT_IPV6_ADDR=xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx/xx
ExecStartPre=/bin/sh -euc ' \
	until ip route show default | grep -qF default; do sleep 1; done'
ExecStart=/bin/sh -euc ' \
	CLIENT_IPV4_ADDR=$$(ip route show default | awk '"'"'NR==1{print($$9)}'"'"'); \
	ip tunnel add he-ipv6 mode sit remote "$${SERVER_IPV4_ADDR:?}" local "$${CLIENT_IPV4_ADDR:?}" ttl 255; \
	ip link set he-ipv6 up mtu 1480; \
	ip addr add "$${CLIENT_IPV6_ADDR:?}" dev he-ipv6; \
	ip route add ::/0 dev he-ipv6'
ExecStop=/bin/sh -euc ' \
	ip route del ::/0 dev he-ipv6; \
	ip link set he-ipv6 down; \
	ip tunnel del he-ipv6'

[Install]
WantedBy=multi-user.target