ip6_gre: Refactor ip6gre xmit codes

This patch refactors the ip6gre_xmit_{ipv4, ipv6}.
It is a prep work to add the ip6erspan tunnel.

Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed