#!/bin/bash
set -Eeuo pipefail
IFACE=$1

source /etc/libvirt/hooks/$IFACE || true

### I need to keep this for backwards compatibility but PUBLICMAC should always be set since it absolutely needs to match the MAC the VM has been assigned by qemu. otherwise nothign will work 
: ${PUBLICMAC:=52:54:00:00:00:11}
###

maxprefixv6=64
maxprefixv4=25

if [ -z $IP ]; then
        echo "got nothing back from the API"
        exit 10
fi

eui64() {
    local macaddr="$1"
    printf "%02x%s" $(( 16#${macaddr:0:2} ^ 2#00000010 )) "${macaddr:2}" \
        | sed -E -e 's/([0-9a-zA-Z]{2})*/0x\0|/g' \
        | tr -d ':\n' \
        | xargs -d '|' \
        printf "fe80::%02x%02x:%02xff:fe%02x:%02x%02x"
}



ip link set up ${IFACE}
ip addr add fe80::1/64 dev ${IFACE}
arp -i ${IFACE} -Ds 169.254.0.1 ${IFACE} netmask 255.255.255.255 pub 



IFS=',' read -ra IPS <<< "$IP"
for IP in "${IPS[@]}"; do
   if [[ $IP =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/([0-9]{2})$ ]]; then			### we got a IPv4 prefix < maxprefixv4
        if [ ${BASH_REMATCH[1]} -lt $maxprefixv4 ]; then
          echo "we don't support such a big customer net?"
          continue
        fi

        if [ ${BASH_REMATCH[1]} -gt 32 ]; then
          echo "prefix is invalid"
          continue
        fi

        echo "we got IPv4 with prefix ${BASH_REMATCH[0]}"
        ip route add ${IP} dev ${IFACE}

     elif [[ $IP =~ ^2604:bbc0:[0-9,a-f,:]{1,444}/([0-9]{2,3})$ ]]; then		### we got a PIv6 prefix < masprefixv6

        if [ ${BASH_REMATCH[1]} -lt $maxprefixv6 ]; then
          echo "we don't support such a big customer net?"
          continue
        fi

        if [ ${BASH_REMATCH[1]} -gt 128 ]; then
          echo "prefix is invalid"
          continue
        fi

        echo "we got IPv6 with prefix ${BASH_REMATCH[0]}"
        ip route add ${IP} dev ${IFACE} via $(eui64 $PUBLICMAC)

     elif [[ $IP =~ ^\ *$ ]]; then
        echo "we just got an empty string. so not gonna do anything. probably due to splitting the comma"

     else
        echo "Unable to detect with what prefix I'm working with"
        exit 10
   fi
done