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--[[
Host address resolver for Alpine Wall
Copyright (C) 2012-2018 Kaarle Ritvanen
See LICENSE file for license details
]]--
local M = {}
local util = require('awall.util')
local familypatterns = {
inet='%d[%.%d/]+', inet6='[:%x/]+', domain='[%a-][%.%w-]*'
}
local function getfamily(addr, context)
for k, v in pairs(familypatterns) do
if addr:match('^'..v..'$') then return k end
end
context:error('Malformed host specification: '..addr)
end
local dnscache = {}
function M.resolve(host, context)
local family = getfamily(host, context)
if family == 'domain' then
if not dnscache[host] then
dnscache[host] = {}
for rec in io.popen('dig '..host..' A '..host..' AAAA'):lines() do
local name, rtype, addr =
rec:match(
'^('..familypatterns.domain..')%s+%d+%s+IN%s+(A+)%s+(.+)'
)
if name and name:sub(1, host:len() + 1) == host..'.' then
if rtype == 'A' then family = 'inet'
elseif rtype == 'AAAA' then family = 'inet6'
else family = nil end
if family then
assert(getfamily(addr, context) == family)
table.insert(dnscache[host], {family, addr})
end
end
end
if not dnscache[host][1] then
context:error('Invalid host name: '..host)
end
table.sort(dnscache[host], function(a, b) return a[2] < b[2] end)
end
return dnscache[host]
end
return {{family, host}}
end
function M.resolvelist(list, context)
local res = {}
for _, host in util.listpairs(list) do
util.extend(res, M.resolve(host, context))
end
return ipairs(res)
end
return M
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