#
# Author:: Adam Jacob (<adam@opscode.com>)
# Copyright:: Copyright (c) 2008 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# 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.
#

require 'ipaddress'
require 'ohai/mixin/network_constants'

Ohai.plugin(:NetworkAddresses) do
  include Ohai::Mixin::NetworkConstants

  provides "ipaddress", "ip6address", "macaddress"

  depends "network/interfaces"

  def sorted_ips(family = "inet")
    raise "bad family #{family}" unless [ "inet", "inet6" ].include? family

    # going to use that later to sort by scope
    scope_prio = [ "global", "site", "link", "host", "node", nil ]

    ipaddresses = []
    # ipaddresses going to hold #{family} ipaddresses and their scope
    Mash[network['interfaces']].each do |iface, iface_v|
      next if iface_v.nil? or not iface_v.has_key? 'addresses'
      iface_v['addresses'].each do |addr, addr_v|
        next if addr_v.nil? or not addr_v.has_key? "family" or addr_v['family'] != family
        ipaddresses <<  {
          :ipaddress => addr_v["prefixlen"] ? IPAddress("#{addr}/#{addr_v["prefixlen"]}") : IPAddress("#{addr}/#{addr_v["netmask"]}"),
          :scope => addr_v["scope"].nil? ? nil : addr_v["scope"].downcase,
          :iface => iface
        }
      end
    end

    # sort ip addresses by scope, by prefixlen and then by ip address
    # 128 - prefixlen: longest prefixes first
    ipaddresses.sort_by do |v|
      [ ( scope_prio.index(v[:scope]) or 999999 ),
        128 - v[:ipaddress].prefix.to_i,
        ( family == "inet" ? v[:ipaddress].to_u32 : v[:ipaddress].to_u128 )
      ]
    end
  end

  def find_ip(family = "inet")
    ips=sorted_ips(family)

    # return if there isn't any #{family} address !
    return [ nil, nil ] if ips.empty?

    # shortcuts to access default #{family} interface and gateway
    int_attr = Ohai::Mixin::NetworkConstants::FAMILIES[family] +"_interface"
    gw_attr = Ohai::Mixin::NetworkConstants::FAMILIES[family] + "_gateway"

    # If we have a default interface that has addresses,
    # populate the short-cut attributes ipaddress, ip6address and macaddress
    if network[int_attr]

      # working with the address(es) of the default network interface
      gw_if_ips = ips.select do |v|
        v[:iface] == network[int_attr]
      end
      if gw_if_ips.empty?
        Ohai::Log.warn("[#{family}] no ip address on #{network[int_attr]}")
      elsif network[gw_attr] and
          network["interfaces"][network[int_attr]] and
          network["interfaces"][network[int_attr]]["addresses"]
        if [ "0.0.0.0", "::", /^fe80:/ ].any? { |pat| pat === network[gw_attr] }
          # link level default route
          Ohai::Log.debug("link level default #{family} route, picking ip from #{network[gw_attr]}")
          r = gw_if_ips.first
        else
          # checking network masks
          r = gw_if_ips.select do |v|
            network_contains_address(network[gw_attr], v[:ipaddress], v[:iface])
          end.first
          if r.nil?
            r = gw_if_ips.first
            Ohai::Log.debug("[#{family}] no ipaddress/mask on #{network[int_attr]} matching the gateway #{network[gw_attr]}, picking #{r[:ipaddress]}")
          else
            Ohai::Log.debug("[#{family}] Using default interface #{network[int_attr]} and default gateway #{network[gw_attr]} to set the default ip to #{r[:ipaddress]}")
          end
        end
      else
        # return the first ip address on network[int_attr]
        r = gw_if_ips.first
      end
    else
      r = ips.first
      Ohai::Log.debug("[#{family}] no default interface, picking the first ipaddress")
    end

    return [ nil, nil ] if r.nil? or r.empty?

    [ r[:ipaddress].to_s, r[:iface] ]
  end

  def find_mac_from_iface(iface)
    r = network["interfaces"][iface]["addresses"].select{|k,v| v["family"]=="lladdr"}
    r.nil? or r.first.nil? ? nil : r.first.first
  end

  def network_contains_address(address_to_match, ipaddress, iface)
    # address_to_match: String
    # ipaddress: IPAddress
    # iface: String
    if peer = network["interfaces"][iface]["addresses"][ipaddress.to_s][:peer]
      IPAddress(peer) == IPAddress(address_to_match)
    else
      ipaddress.include? IPAddress(address_to_match)
    end
  end

  # ipaddress, ip6address and macaddress can be set by the #{os}::network plugin
  # atm it is expected macaddress is set at the same time than ipaddress
  # if ipaddress is set and macaddress is nil, that means the interface
  # ipaddress is bound to has the NOARP flag

  collect_data do
    results = {}

    network Mash.new unless network
    network[:interfaces] = Mash.new unless network[:interfaces]
    counters Mash.new unless counters
    counters[:network] = Mash.new unless counters[:network]

    # inet family is treated before inet6
    Ohai::Mixin::NetworkConstants::FAMILIES.keys.sort.each do |family|
      r = {}
      ( r["ip"], r["iface"] ) = find_ip(family)
      r["mac"] = find_mac_from_iface(r["iface"]) unless r["iface"].nil?
      # don't overwrite attributes if they've already been set by the "#{os}::network" plugin
      if family == "inet" and ipaddress.nil?
        if r["ip"].nil?
          Ohai::Log.warn("unable to detect ipaddress")
          # i don't issue this warning if r["ip"] exists and r["mac"].nil?
          # as it could be a valid setup with a NOARP default_interface
          Ohai::Log.warn("unable to detect macaddress")
        else
          ipaddress r["ip"]
          macaddress r["mac"]
        end
      elsif family == "inet6" and ip6address.nil?
        if r["ip"].nil?
          Ohai::Log.debug("unable to detect ip6address")
        else
          ip6address r["ip"]
          if r["mac"] and macaddress.nil? and ipaddress.nil?
            Ohai::Log.debug("macaddress set to #{r["mac"]} from the ipv6 setup")
            macaddress r["mac"]
          end
        end
      end
      results[family] = r
    end

    if results["inet"]["iface"] and results["inet6"]["iface"] and
        results["inet"]["iface"] != results["inet6"]["iface"]
      Ohai::Log.debug("ipaddress and ip6address are set from different interfaces (#{results["inet"]["iface"]} & #{results["inet6"]["iface"]}), macaddress has been set using the ipaddress interface")
    end
  end
end