pm_dhcpd.lua

#!/usr/bin/env lua
-- -*-lua-*-
--
-- $Id: pm_dhcpd.lua $
--
-- Author: Markus Stenberg <markus stenberg@iki.fi>
--
-- Copyright (c) 2012 cisco Systems, Inc.
--
-- Created:       Thu Nov  8 06:54:56 2012 mstenber
-- Last modified: Mon Sep 30 17:16:25 2013 mstenber
-- Edit time:     14 min
--

require 'pm_handler'

module(..., package.seeall)

local _null=string.char(0)

DHCPD_SCRIPT='/usr/share/hnet/dhcpd_handler.sh'

local _parent = pm_handler.pm_handler_with_pa_dns

pm_dhcpd = _parent:new_subclass{class='pm_dhcpd'}

function pm_dhcpd:run()
   local fpath = self.config.dhcpd_conf_filename
   local owned4 = self:write_dhcpd_conf(fpath)
   local s = string.format('%s 4 %s %s', DHCPD_SCRIPT, tostring(owned4), fpath)
   self.shell(s)


   -- if we're doing v4 only, don't do anything about v6
   if self.config.use_fakedhcpv6d
   then
      return
   end

   local fpath = self.config.dhcpd6_conf_filename
   local owned6 = self:write_dhcpd6_conf(fpath)

   local s = string.format('%s 6 %s %s', DHCPD_SCRIPT, tostring(owned6), fpath)
   self.shell(s)
end

function pm_dhcpd:write_dhcpd_conf(fpath)
   local owned = 0
   self:d('entered write_dhcpd_conf')

   local fpath = fpath

   local t = mst.array:new{}

   local dns = self.ospf_v4_dns or {}
   self:dump_address_list_option(t, dns, 'domain-name-servers')

   local search = self.ospf_v4_dns_search or {}
   self:dump_search_list_option(t, search, 'domain-search')

   if #dns == 0
   then
      t:insert([[
                   # we don't have good information yet, keep asking!
max-lease-time 30;
]])
   end

   -- for each locally assigned prefix, if we're the owner (=publisher
   -- of asp), run DHCPv4 otherwise not..
   handled = mst.set:new{}
   for i, lap in ipairs(self.lap)
   do
      local dep = lap.depracate      
      local own = lap.owner and not lap.external
      -- this is used to prevent more than one subnet per interface
      -- (sigh, ISC DHCP limitation #N)
      local already_done = handled[lap.ifname]
      if not dep and own and not already_done and lap.address
      then
         local p = ipv6s.ipv6_prefix:new{ascii=lap.prefix}
         if p:is_ipv4()
         then
            handled:insert(lap.ifname)
            local myip = mst.string_split(lap.address, '/')[1]
            owned = owned + 1
            local b = p:get_binary()
            local snb = b .. _null
            local sn = ipv6s.binary_address_to_address(snb)
            local stb = b .. string.char(pa.IPV4_PA_LAST_ROUTER + 1)
            local enb = b .. string.char(254)
            local st = ipv6s.binary_address_to_address(stb)
            local en = ipv6s.binary_address_to_address(enb)
            t:insert('subnet ' .. sn .. ' netmask 255.255.255.0 {')
            t:insert('  range ' .. st .. ' ' .. en .. ';')
            t:insert('  option routers ' .. myip .. ';')
            t:insert('}')
         end
      end
   end

   self:write_to_file(fpath, t, '# ')

   return owned
end

function pm_dhcpd:write_dhcpd6_conf(fpath)
   local owned = 0
   self:d('entered write_dhcpd6_conf')

   local t = mst.array:new{}

   t:insert([[
                   # dhcpd6.conf
                   # automatically generated by pm_core.lua
                ]])
   
   local dns = self.ospf_dns or {}
   self:dump_address_list_option(t, dns, 'dhcp6.name-servers')

   local search = self.ospf_dns_search or {}
   self:dump_search_list_option(t, search, 'dhcp6.domain-search')

   -- for each locally assigned prefix, if we're the owner (=publisher
   -- of asp), run DHCPv6, otherwise not..
   handled = mst.set:new{}
   for i, lap in ipairs(self.lap)
   do
      self:a(not lap[elsa_pa.PREFIX_CLASS_KEY], 
            'prefix classes not supported in ISC DHCPv6d yet')
      local dep = lap.depracate      
      local own = lap.owner and not lap.external
      -- this is used to prevent more than one subnet per interface
      -- (sigh, ISC DHCP limitation #N)
      local already_done = handled[lap.ifname]
      if not dep and own and not already_done
      then
         local p = ipv6s.ipv6_prefix:new{ascii=lap.prefix}
         if not p:is_ipv4()
         then
            handled:insert(lap.ifname)
            owned = owned + 1
            local b = p:get_binary()
            local stb = b .. string.rep(_null, 7) .. string.char(42)
            local enb = b .. string.rep(_null, 7) .. string.char(123)
            local st = ipv6s.binary_address_to_address(stb)
            local en = ipv6s.binary_address_to_address(enb)
            t:insert('subnet6 ' .. lap.prefix .. ' {')
            t:insert('  range6 ' .. st .. ' ' .. en .. ';')
            t:insert('}')
         end
      end
   end

   self:write_to_file(fpath, t, '# ')

   return owned
end

function pm_dhcpd:dump_address_list_option(t, l, option_name)
   if #l == 0
   then
      return
   end
   l = mst.array_filter(l, function (v)
                           return #mst.string_strip(v) > 0
                        end)
   local s = table.concat(l,",")
   -- if we have multiple ones from e.g. shell, separator may be
   -- space too
   s = string.gsub(s, ' ', ',') 
   t:insert('option ' .. option_name .. ' ' .. s .. ';')
end

function pm_dhcpd:dump_search_list_option(t, l, option_name)
   if #l == 0
   then
      return
   end
   local r = mst.array:new{}
   for i, v0 in ipairs(l)
   do
      for i, v in ipairs(mst.string_split(v0, ' '))
      do
         v = mst.string_strip(v)
         if #v > 0
         then
            r:insert(mst.repr(v))
         end
      end
   end
   -- may also skip if results were just whitespaces or something
   if #r == 0
   then
      return
   end
   local s = table.concat(r, ",")
   t:insert('option ' .. option_name .. ' ' .. s .. ';')
end