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

if [ ${#IFACE} -gt 15 ]; then
   echo "interface name too long, mac 14 char: $IFACE"
   exit 10
fi

VNI=$(printf '%d' $((16#${IFACE##*.})))

if ! [[ $VNI =~ ^[0-9]+$ ]]; then
    echo "VNI '$VNI' seems not to be valid"
    exit 10
fi

LOOPBACKIP=$(ip -4 addr show dev lo | grep -Po 'inet \K[\d.]+' | grep -v "^127.0.0.1$")
BRIDGE=br${VNI}
VIF=vxlan${VNI}
[ -z ${PARENTIF:=""} ] || VIF=vlan${VNI}                                ### if we have a parentif set we're just going to handle it as a legacy old school vlan

ip link set up ${IFACE}

if ! ip link show dev ${VIF} &>/dev/null; then 
    if [ -z ${PARENTIF:=""} ]
      then
        ip link add ${VIF} type vxlan id ${VNI} dstport 4789 local ${LOOPBACKIP} nolearning
      else
        ip link add link ${PARENTIF} name ${VIF} type vlan protocol 802.1q id ${VNI}
    fi
    ip link set up ${VIF}
fi

if ! ip link show dev ${BRIDGE} &>/dev/null; then 
    brctl addbr ${BRIDGE}
    brctl stp ${BRIDGE} off
    brctl addif ${BRIDGE} ${VIF} 
    ip link set up dev ${BRIDGE}
    bridge vlan del dev ${BRIDGE} vid 1 self
    echo 1 >/sys/class/net/${BRIDGE}/bridge/vlan_filtering
fi

brctl addif ${BRIDGE} ${IFACE}