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local adns = require "net.adns";
local inet_pton = require "util.net".pton;
local inet_ntop = require "util.net".ntop;
local idna_to_ascii = require "util.encodings".idna.to_ascii;
local unpack = table.unpack or unpack; -- luacheck: ignore 113
local methods = {};
local resolver_mt = { __index = methods };
-- FIXME RFC 6724
-- Find the next target to connect to, and
-- pass it to cb()
function methods:next(cb)
if self.targets then
if #self.targets == 0 then
cb(nil);
return;
end
local next_target = table.remove(self.targets, 1);
cb(unpack(next_target, 1, 4));
return;
end
if not self.hostname then
-- FIXME report IDNA error
cb(nil);
return;
end
local secure = true;
local tlsa = {};
local targets = {};
local n = 3;
local function ready()
n = n - 1;
if n > 0 then return; end
self.targets = targets;
if self.extra and self.extra.use_dane then
if secure and tlsa[1] then
self.extra.tlsa = tlsa;
self.extra.dane_hostname = self.hostname;
else
self.extra.tlsa = nil;
self.extra.dane_hostname = nil;
end
end
self:next(cb);
end
-- Resolve DNS to target list
local dns_resolver = adns.resolver();
if not self.extra or self.extra.use_ipv4 ~= false then
dns_resolver:lookup(function (answer)
if answer then
secure = secure and answer.secure;
for _, record in ipairs(answer) do
table.insert(targets, { self.conn_type.."4", record.a, self.port, self.extra });
end
end
ready();
end, self.hostname, "A", "IN");
else
ready();
end
if not self.extra or self.extra.use_ipv6 ~= false then
dns_resolver:lookup(function (answer)
if answer then
secure = secure and answer.secure;
for _, record in ipairs(answer) do
table.insert(targets, { self.conn_type.."6", record.aaaa, self.port, self.extra });
end
end
ready();
end, self.hostname, "AAAA", "IN");
end
if self.extra and self.extra.use_dane == true then
dns_resolver:lookup(function (answer)
if answer then
secure = secure and answer.secure;
for _, record in ipairs(answer) do
table.insert(tlsa, record.tlsa);
end
end
ready();
end, ("_%d._tcp.%s"):format(self.port, self.hostname), "TLSA", "IN");
else
ready();
end
end
local function new(hostname, port, conn_type, extra)
local ascii_host = idna_to_ascii(hostname);
local targets = nil;
conn_type = conn_type or "tcp";
local is_ip = inet_pton(hostname);
if not is_ip and hostname:sub(1,1) == '[' then
is_ip = inet_pton(hostname:sub(2,-2));
end
if is_ip then
hostname = inet_ntop(is_ip);
if #is_ip == 16 then
targets = { { conn_type.."6", hostname, port, extra } };
elseif #is_ip == 4 then
targets = { { conn_type.."4", hostname, port, extra } };
end
end
return setmetatable({
hostname = ascii_host;
port = port;
conn_type = conn_type;
extra = extra;
targets = targets;
}, resolver_mt);
end
return {
new = new;
};
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