#!/bin/bash

function exec_command {
  eval "${1}"
}

function up_bridge {
  local vpc="${1}"
  local bridge="br-${2}"
  local exec=""

  if [[ "${vpc}" != "" ]]
  then
    exec="ip netns exec ${vpc}"
  fi

  exec_command "${exec} brctl addbr ${bridge}"
  exec_command "${exec} brctl stp ${bridge} off"
  exec_command "${exec} ip link set up dev ${bridge}"
}

function up_vxlan {
  local id="${1}"
  local local_ip="${2}"
  local bridge="br-${3}"

  ip link add "vxlan-${id}" type vxlan \
    id "${id}" \
    dstport 4789 \
    local "${local_ip}" \
    nolearning
  brctl addif "${bridge}" "vxlan-${id}"
  ip link set up dev "vxlan-${id}"
}

function up_netns {
  local netns="${1}"
  local subnet="${2}"
  local veth="veth-${subnet}"

  ip               netns add "${netns}"
  ip               link add "${veth}-ext" type veth peer name "${veth}-int" netns ${netns}
  ip               link set up dev "${veth}-ext"
  ip -n "${netns}" link set up dev "${veth}-int"
}

INTERFACE="eno1"
LOCAL_IP=$(ip a | grep -E "^ .*${INTERFACE}$" | sed 's/  */ /g' | cut -d\  -f 3|cut -d\/ -f1)
VXLAN_ID="${2}"
SUBNET_NAME="${3}"
VPC_NAME="${4}"
TAP_NAME="${5}"

echo "Create vm subnet"
echo " -> interface name : ${INTERFACE}"
echo " -> interface ip   : ${LOCAL_IP}"
echo " -> vxlan id       : ${VXLAN_ID}"
echo " -> subnet name    : ${SUBNET_NAME}"
echo " -> vpn            : ${VPC_NAME}"
echo " -> tapid          : ${TAP_NAME}"

up_netns "${VPC_NAME}" "${SUBNET_NAME}"

up_bridge "" "${SUBNET_NAME}"
up_bridge "${VPC_NAME}" "${SUBNET_NAME}"

up_vxlan "${VXLAN_ID}" "${LOCAL_IP}" "${SUBNET_NAME}"


brctl addif "br-${SUBNET_NAME}" "veth-${SUBNET_NAME}-ext"
ip netns exec "${VPC_NAME}" brctl addif "br-${SUBNET_NAME}" "veth-${SUBNET_NAME}-int"

ip -n "${VPC_NAME}" tuntap add dev "tap${TAP_NAME}" mode tap
ip -n "${VPC_NAME}" link set up dev "tap${TAP_NAME}"
ip netns exec "${VPC_NAME}" brctl addif "br-${SUBNET_NAME}" "tap${TAP_NAME}"