File

net/resolvers/basic.lua @ 9830:d935a0f0de24

MUC: Factor out role change permission check into its own method I would like to invert this logic so that it checks if the role change is allowed instead of checking if it is not allowed as it does now, in order to make it easier to understand.
author Kim Alvefur <zash@zash.se>
date Sun, 24 Feb 2019 16:18:30 +0100 (2019-02-24)
parent 9691:e11e076f0eb8
child 10386:cf93a951da37
line wrap: on
line source
local adns = require "net.adns";
local inet_pton = require "util.net".pton;
local unpack = table.unpack or unpack; -- luacheck: ignore 113

local methods = {};
local resolver_mt = { __index = methods };

-- 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

	local targets = {};
	local n = 2;
	local function ready()
		n = n - 1;
		if n > 0 then return; end
		self.targets = targets;
		self:next(cb);
	end

	local is_ip = inet_pton(self.hostname);
	if is_ip then
		if #is_ip == 16 then
			cb(self.conn_type.."6", self.hostname, self.port, self.extra);
		elseif #is_ip == 4 then
			cb(self.conn_type.."4", self.hostname, self.port, self.extra);
		end
		return;
	end

	-- Resolve DNS to target list
	local dns_resolver = adns.resolver();
	dns_resolver:lookup(function (answer)
		if answer then
			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");

	dns_resolver:lookup(function (answer)
		if answer then
			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

local function new(hostname, port, conn_type, extra)
	return setmetatable({
		hostname = hostname;
		port = port;
		conn_type = conn_type or "tcp";
		extra = extra;
	}, resolver_mt);
end

return {
	new = new;
};