#!/bin/sh

COMMENTED=^[[:blank:]]*#
arg0=${0##*/}

# $1 stores the prefix (the input parameter of mappingprefixadd) 
PD_result=$1

# modify Intif to fit your environment
LANif=br-lan

# the subperfix len of LAN is always 64 (may be changed if the device allows prefix delegation from LAN)
Subprefix_len=64

# $Subprefix is to be used in sed, so the '/' need to be escaped especially
Subprefix="$PD_result\/$Subprefix_len"
#echo "Subprefix $Subprefix"

# global address of the LAN link 
LLA=`ifconfig $LANif | grep 'Scope:Link' | awk '{print $3}'`
# compose the GUA prefix and the EUI-64 part
pd4=`echo $PD_result | cut -d':' -f4`
if [ -z $pd4 ]; then
    LANaddrv6=`echo $PD_result$LLA | sed 's!::.*::!::!`
else
    LANaddrv6=`echo $PD_result$LLA | sed 's!::.*::!:!`
fi

echo "$LANif subnet prefix: $1/$Subprefix_len"

# check existing GUA
GUA=`ifconfig $LANif | grep ' [23].*Global' | awk '{print $3}'`
GUA_prefix4=`echo $GUA | cut -c1-1`
echo "get existing GUA: $GUA, GUA/4: $GUA_prefix4"

# del old GUA
if [ "$GUA_prefix4" == "2" -o "$GUA_prefix4" == "3" ]; then
    ifconfig $LANif del $GUA
fi
# add an IPv6 address for the internal interface
ifconfig $LANif add $LANaddrv6

#restart internal DNS server
echo "restart internal name server"
/etc/init.d/named restart

# change M flag from off to on if necessary
grep -q "option AdvManagedFlag[[:blank:]]*1" /etc/config/radvd
if [ $? -eq 0 ]; then
    sed 's/AdvManagedFlag[ '$'\t'']*off/AdvManagedFlag on/g' /var/etc/radvd.conf > /var/etc/radvd.conf.tmp
    mv -f /var/etc/radvd.conf.tmp /var/etc/radvd.conf
fi

# replace the GUA prefix configuration in /var/etc/radvd.conf
valid_time=$(grep AdvValidLifetime /etc/config/radvd | awk '{ print $3}')
preferred_time=$(grep AdvPreferredLifetime /etc/config/radvd | awk '{ print $3}')
PREFIX_OPTION="\tprefix $Subprefix\n\t{\n\t\tAdvValidLifetime $valid_time;\n\t\tAdvPreferredLifetime $preferred_time;\n\t\tAdvOnLink on;\n\t\tAdvAutonomous on;\n\t\tAdvRouterAddr off;\n\t};"
#echo "$PREFIX_OPTION"

set -- $(awk "BEGIN { SEC_B=0 } /$COMMENTED/ { next; } /prefix[[:blank:]]*[23].*/ { SEC_B=NR } /^[[:blank:]]*\}/ { if(SEC_B!=0) { print 1, SEC_B, NR; exit; } } END { print 0 }" /var/etc/radvd.conf)
found=$1
if [ "$found" == "1" ]; then
    LB=$2
    LE=$3
    eval "sed -e '$LB,$LE d' /var/etc/radvd.conf > /var/etc/radvd.conf.tmp"
    eval "sed -e '$LB i\#tag-to-ins' /var/etc/radvd.conf.tmp | sed 's/^#tag-to-ins/$PREFIX_OPTION/g' > /var/etc/radvd.conf"
    rm /var/etc/radvd.conf.tmp
else
    eval "sed -e '/AdvOtherConfigFlag/a\#tag-to-ins' /var/etc/radvd.conf | sed 's/^#tag-to-ins/$PREFIX_OPTION/g' > /var/etc/radvd.conf.tmp"
    mv -f /var/etc/radvd.conf.tmp /var/etc/radvd.conf
fi

# (re)start radvd
#/etc/init.d/radvd restart || /etc/init.d/radvd start
killall -q -KILL radvd
rm /var/run/radvd.pid
radvd -C /var/etc/radvd.conf -m stderr_syslog -p /var/run/radvd.pid

# update IA_NA pool in /var/etc/dibbler/server.conf
IA_NA_POOL="\tclass {\n\t\tpool $Subprefix\n\t}"
set -- $(awk "BEGIN { SEC_B=0 } /$COMMENTED/ { next; } /stateless/ { print 0, NR; exit; } /^[[:blank:]]*class/ { SEC_B=NR } /^[[:blank:]]*\}/ { if(SEC_B!=0) { print 1, SEC_B, NR; exit; } } END { print 2 }" /var/etc/dibbler/server.conf)
stateful=$1
case $stateful in
    "0")
        # stateless, check if it's needed to switch to stateful
        LB=$2
        grep -v "$COMMENTED" /etc/config/dibbler/server.conf | grep -q 'stateless'
        if [ $? -eq 1 ]; then
            eval "sed -e '$LB,$LB d' /var/etc/dibbler/server.conf > /var/etc/dibbler/server.conf.tmp"
            eval "sed -e '/valid-lifetime/a\#tag-to-ins' /var/etc/dibbler/server.conf.tmp | sed 's/^#tag-to-ins/$IA_NA_POOL/g' > /var/etc/dibbler/server.conf"
            rm /var/etc/dibbler/server.conf.tmp
        fi
        ;;
    "1")
        # stateful with IA_NA pool, replace it
        LB=$2
        LE=$3
        eval "sed -e '$LB,$LE d' /var/etc/dibbler/server.conf > /var/etc/dibbler/server.conf.tmp"
        eval "sed -e '$LB i\#tag-to-ins' /var/etc/dibbler/server.conf.tmp | sed 's/^#tag-to-ins/$IA_NA_POOL/g' > /var/etc/dibbler/server.conf"
        rm /var/etc/dibbler/server.conf.tmp
        ;;
    "2")
        # stateful with no IA_NA pool, should not happen
        echo "stateful DHCPv6 server w/o IA_NA pool"
        ;;
    *)
        ;;
esac

#set -- $(awk 'BEGIN { LB=0 } /^[ \t#]*class/ { LB=NR } /^[ \t#]*\}/ { if(LB!=0) { print LB, NR; exit; } }' /var/etc/dibbler/server.conf)
#LB=$1
#LE=$2
## skip comments and try to find "stateless"
#grep -v '^[ '$'\t'']*#' /var/etc/dibbler/server.conf | grep -q 'stateless'
#if [ $? -eq 1 ]; then
#    eval "sed -e '$LB,$LE d' /var/etc/dibbler/server.conf > /var/etc/dibbler/server.conf.tmp"
#    eval "sed -e '$LB i\#tag-to-ins' /var/etc/dibbler/server.conf.tmp | sed 's/^#tag-to-ins/$IA_NA_POOL/g' > /var/etc/dibbler/server.conf"
#    rm /var/etc/dibbler/server.conf.tmp  
#fi

# (re)start dibbler-server
dibbler-server stop
dibbler-server start

# show ipv6 addresses and routes
#ip -6 addr show
#ip -6 route show