IPv6 scritp for DD-WRT

ipv6.sh

#!/bin/sh
#

fakeipv6=$(ip -6 addr |grep '240e:c2:f803:2d00:200:ff:fe00:0/56')
nvramcfg=$(ip -6 route |grep '/64 dev ppp0' |awk '{print $1}' |awk -F / '{print $1}')

if [ -n "$fakeipv6" ]
then
  (ip -6 addr del 240e:c2:f803:2d00:200:ff:fe00:0/56 dev br0)
  nvram unset ipv6_rtr_addr
  nvram set ipv6_get_dns="240c::6666 240c::6644"
  nvram set ipv6_prefix="$nvramcfg"
fi

ppp0route=$(ip -6 route |grep '/64 dev ppp0' |awk '{print $1}')
ppp0ipaddr=$(ip -6 addr |grep 'scope global dynamic' |awk '{print $2}')
br0route=$(ip -6 route |grep '/64 dev br0  metric 128' |awk '{print $1}')
br0ipaddr=$(ip -6 addr |grep -A 1 br0 |grep inet6 |awk '{print $2}')

if [ "$br0route" != "$ppp0route" ]
then
  if [ -n "$ppp0route" ]
  then
    if [ "$br0route" != "$ppp0route" ]
    then
      if [ -z "$br0route" ]
      then
        ip -6 addr add "$ppp0ipaddr" dev br0
        ip -6 route del "$ppp0route" dev br0
        ip -6 route add "$ppp0route" dev br0 metric 128
        nvram unset ipv6_rtr_addr
        nvram set ipv6_get_dns="240c::6666 240c::6644"
        nvram set ipv6_prefix="$nvramcfg"
      else
        ip -6 addr del "$br0ipaddr" dev br0
        ip -6 addr add "$ppp0ipaddr" dev br0
        ip -6 route del "$ppp0route" dev br0
        ip -6 route add "$ppp0route" dev br0 metric 128
        nvram unset ipv6_rtr_addr
        nvram set ipv6_get_dns="240c::6666 240c::6644"
        nvram set ipv6_prefix="$nvramcfg"
      fi
    fi
  fi
fi

exit 0