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--[[
Iptables file dumper for Alpine Wall
Copyright (C) 2012-2013 Kaarle Ritvanen
See LICENSE file for license details
]]--
module(..., package.seeall)
require 'lpc'
require 'awall.object'
require 'awall.uerror'
local util = require('awall.util')
local sortedkeys = util.sortedkeys
local class = awall.object.class
local families = {inet={cmd='iptables',
file='rules-save',
procfile='/proc/net/ip_tables_names'},
inet6={cmd='ip6tables',
file='rules6-save',
procfile='/proc/net/ip6_tables_names'}}
builtin = {filter={'FORWARD', 'INPUT', 'OUTPUT'},
mangle={'FORWARD', 'INPUT', 'OUTPUT', 'POSTROUTING', 'PREROUTING'},
nat={'INPUT', 'OUTPUT', 'POSTROUTING', 'PREROUTING'},
raw={'OUTPUT', 'PREROUTING'},
security={'FORWARD', 'INPUT', 'OUTPUT'}}
local backupdir = '/var/run/awall'
local BaseIPTables = class()
function BaseIPTables:print()
for family, tbls in pairs(families) do
self:dumpfile(family, io.stdout)
print()
end
end
function BaseIPTables:dump(dir)
for family, tbls in pairs(families) do
local file = io.output(dir..'/'..families[family].file)
self:dumpfile(family, file)
file:close()
end
end
function BaseIPTables:restore(test)
local disabled = true
for family, params in pairs(families) do
local file = io.open(params.procfile)
if file then
io.close(file)
local pid, stdin, stdout = lpc.run(params.cmd..'-restore',
unpack({test and '-t' or nil}))
stdout:close()
self:dumpfile(family, stdin)
stdin:close()
assert(lpc.wait(pid) == 0)
disabled = false
elseif test then
io.stderr:write('Warning: '..family..' rules not tested\n')
end
end
if disabled then awall.uerror.raise('Firewall not enabled in kernel') end
end
function BaseIPTables:activate()
flush()
self:restore(false)
end
function BaseIPTables:test() self:restore(true) end
IPTables = class(BaseIPTables)
function IPTables:init()
self.config = {}
setmetatable(self.config,
{__index=function(t, k)
t[k] = {}
setmetatable(t[k], getmetatable(t))
return t[k]
end})
end
function IPTables:dumpfile(family, iptfile)
iptfile:write('# '..families[family].file..' generated by awall\n')
local tables = self.config[family]
for i, tbl in sortedkeys(tables) do
iptfile:write('*'..tbl..'\n')
local chains = tables[tbl]
for i, chain in sortedkeys(chains) do
local policy = '-'
if util.contains(builtin[tbl], chain) then
policy = tbl == 'filter' and 'DROP' or 'ACCEPT'
end
iptfile:write(':'..chain..' '..policy..' [0:0]\n')
end
for i, chain in sortedkeys(chains) do
for i, rule in ipairs(chains[chain]) do
iptfile:write('-A '..chain..' '..rule..'\n')
end
end
iptfile:write('COMMIT\n')
end
end
local Current = class(BaseIPTables)
function Current:dumpfile(family, iptfile)
local pid, stdin, stdout = lpc.run(families[family].cmd..'-save')
stdin:close()
for line in stdout:lines() do iptfile:write(line..'\n') end
stdout:close()
assert(lpc.wait(pid) == 0)
end
local Backup = class(BaseIPTables)
function Backup:dumpfile(family, iptfile)
for line in io.lines(backupdir..'/'..families[family].file) do
iptfile:write(line..'\n')
end
end
function backup()
Current.new():dump(backupdir)
end
function revert()
Backup.new():activate()
end
function flush()
local empty = IPTables.new()
for family, params in pairs(families) do
local success, lines = pcall(io.lines, params.procfile)
if success then
for tbl in lines do
for i, chain in ipairs(builtin[tbl]) do
empty.config[family][tbl][chain] = {}
end
end
end
end
empty:restore(false)
end
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