#!/usr/bin/env ruby

# -------------------------------------------------------------------------- #
# Copyright 2002-2020, OpenNebula Project, OpenNebula Systems                #
#                                                                            #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    #
# not use this file except in compliance with the License. You may obtain    #
# a copy of the License at                                                   #
#                                                                            #
# http://www.apache.org/licenses/LICENSE-2.0                                 #
#                                                                            #
# Unless required by applicable law or agreed to in writing, software        #
# distributed under the License is distributed on an "AS IS" BASIS,          #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   #
# See the License for the specific language governing permissions and        #
# limitations under the License.                                             #
#--------------------------------------------------------------------------- #

MAP_VNETS_START_SCRIPT_LOGFILE = '/var/log/map_vnets_start_script.log'

IPTABLES_NAT_PREFIX = 'iptables -tnat'

CHAIN_VROUTER_SNAT = 'chain-vrouter-snat'
CHAIN_VROUTER_DNAT = 'chain-vrouter-dnat'

require 'json'
require 'logger'
require 'tempfile'

log = Logger.new(MAP_VNETS_START_SCRIPT_LOGFILE.to_s, 'daily')
log.level = Logger::INFO

log.info 'map_vnets_start_script executed'

service = JSON.parse(`onegate service show --json --extended`)
log.debug "Service: #{service}"

sdnats = []

roles = service['SERVICE']['roles'].flatten
roles.each do |role|
    next unless role['nodes']

    role['nodes'].each do |node|
        nic_aliases = [node['vm_info']['VM']['TEMPLATE']['NIC_ALIAS']].flatten
        next unless nic_aliases.any?

        nics = [node['vm_info']['VM']['TEMPLATE']['NIC']].flatten
        nic_aliases.each do |nic_alias|
            nic = nics.detect {|n| n['NAME'] == nic_alias['PARENT'] }
            sdnats << { 'NIC' => nic['IP'], 'NIC_ALIAS' => nic_alias['IP'] }
        end
    end
end

log.debug "IPs: #{sdnats}"

rules = ''

begin
    f = Tempfile.new

    f << `iptables -tnat -S #{CHAIN_VROUTER_DNAT} >/dev/null 2>&1 ||\
          echo "-N #{CHAIN_VROUTER_DNAT}"`
    f << `iptables -tnat -S #{CHAIN_VROUTER_SNAT} >/dev/null 2>&1 ||\
          echo "-N #{CHAIN_VROUTER_SNAT}"`
    f << `iptables -tnat -C PREROUTING -j #{CHAIN_VROUTER_DNAT} 2>/dev/null ||\
          echo "-A PREROUTING -j #{CHAIN_VROUTER_DNAT}"`
    f << `iptables -tnat -C POSTROUTING -j #{CHAIN_VROUTER_SNAT} 2>/dev/null ||\
          echo "-A POSTROUTING -j #{CHAIN_VROUTER_SNAT}"`

    f << `iptables -t nat -S #{CHAIN_VROUTER_DNAT} 2>/dev/null |\
          sed -n 's/-A\\(.*\\)/-D\\1/p'`
    f << `iptables -t nat -S #{CHAIN_VROUTER_SNAT} 2>/dev/null |\
          sed -n 's/-A\\(.*\\)/-D\\1/p'`

    f.close

    sdnats.each do |nat|
        `iptables -tnat -C #{CHAIN_VROUTER_DNAT} -d #{nat['NIC_ALIAS']} -j DNAT\
         --to-destination #{nat['NIC']} 2>/dev/null &&\
         sed -i '/.*#{CHAIN_VROUTER_DNAT} -d #{nat['NIC_ALIAS']}\\/32 -j DNAT \
--to-destination #{nat['NIC']}/d' #{f.path} ||\
         echo '-A #{CHAIN_VROUTER_DNAT} -d #{nat['NIC_ALIAS']} -j DNAT \
         --to-destination #{nat['NIC']}' >> #{f.path}`

        `iptables -tnat -C #{CHAIN_VROUTER_SNAT} -s #{nat['NIC']} -j SNAT \
         --to-source #{nat['NIC_ALIAS']} 2>/dev/null &&\
         sed -i '/.*#{CHAIN_VROUTER_SNAT} -s #{nat['NIC']}\\/32 -j SNAT \
--to-source #{nat['NIC_ALIAS']}/d' #{f.path}||\
         echo '-A #{CHAIN_VROUTER_SNAT} -s #{nat['NIC']} -j SNAT \
         --to-source #{nat['NIC_ALIAS']}' >> #{f.path}`
    end

    rules << `cat #{f.path}`
ensure
    f.unlink
end

log.debug "Rules: #{rules}"

rules.each_line do |rule|
    `iptables -tnat #{rule}`
end

log.debug "iptables-save: #{`iptables-save`}"