#!/usr/bin/lua

local nixio = require 'nixio'
local sysconfig = require 'gluon.sysconfig'
local uci = require('luci.model.uci').cursor()
local site = require 'gluon.site_config'


function IPv6(address)
--[[
(c) 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
(c) 2008 Steven Barth <steven@midlink.org>

Licensed under the Apache License, Version 2.0 (the "License").
You may obtain a copy of the License at

	        http://www.apache.org/licenses/LICENSE-2.0
]]--
	local data = {}

	local borderl = address:sub(1, 1) == ":" and 2 or 1
	local borderh, zeroh, chunk, block

	if #address > 45 then return nil end

	repeat
		borderh = address:find(":", borderl, true)
		if not borderh then break end

		block = tonumber(address:sub(borderl, borderh - 1), 16)
		if block and block <= 0xFFFF then
			data[#data+1] = block
		else
			if zeroh or borderh - borderl > 1 then return nil end
			zeroh = #data + 1
		end

		borderl = borderh + 1
	until #data == 7

	chunk = address:sub(borderl)
	if #chunk > 0 and #chunk <= 4 then
		block = tonumber(chunk, 16)
		if not block or block > 0xFFFF then return nil end

		data[#data+1] = block
	elseif #chunk > 4 then
		if #data == 7 or #chunk > 15 then return nil end
		borderl = 1
		for i=1, 4 do
			borderh = chunk:find(".", borderl, true)
			if not borderh and i < 4 then return nil end
			borderh = borderh and borderh - 1

			block = tonumber(chunk:sub(borderl, borderh))
			if not block or block > 255 then return nil end

			if i == 1 or i == 3 then
				data[#data+1] = block * 256
			else
				data[#data] = data[#data] + block
			end

			borderl = borderh and borderh + 2
		end
	end

	if zeroh then
		if #data == 8 then return nil end
		while #data < 8 do
			table.insert(data, zeroh, 0)
		end
	end

	if #data == 8 then
		return data[1], data[2], data[3], data[4], data[5], data[6], data[7], data[8]
	end
end

function mac_to_ip(prefix, mac)
  local m1, m2, m3, m6, m7, m8 = string.match(mac, '(%x%x):(%x%x):(%x%x):(%x%x):(%x%x):(%x%x)')
  local m4 = 0xff
  local m5 = 0xfe
  m1 = nixio.bit.bxor(tonumber(m1, 16), 0x02)

  local h1 = 0x100 * m1 + tonumber(m2, 16)
  local h2 = 0x100 * tonumber(m3, 16) + m4
  local h3 = 0x100 * m5 + tonumber(m6, 16)
  local h4 = 0x100 * tonumber(m7, 16) + tonumber(m8, 16)

  local prefix, plen = string.match(prefix, '(.*)/(%d+)')
  plen = tonumber(plen, 10)

  local p1, p2, p3, p4, p5, p6, p7, p8 = IPv6(prefix)

  return string.format("%x:%x:%x:%x:%x:%x:%x:%x/%d", p1, p2, p3, p4, h1, h2, h3, h4, 128)
end

local ip = mac_to_ip(site.babel_mesh.prefix, sysconfig.primary_mac)

uci:set('network', 'loopback', 'ip6addr', ip)
uci:save('network')
uci:commit('network')