File

net/unbound.lua @ 13107:9c4dc1e6d2c9

mod_http: Add way to retrieve internal URL instead of external This could be of help when configuring reverse proxies, as it is the internal URL the proxy must point at. Argument treated as an enum "internal" "external"(default) to allow for future extensibility.
author Kim Alvefur <zash@zash.se>
date Wed, 24 May 2023 14:43:45 +0200
parent 12974:ba409c67353b
line wrap: on
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-- libunbound based net.adns replacement for Prosody IM
-- Copyright (C) 2013-2015 Kim Alvefur
--
-- This file is MIT licensed.
--
-- luacheck: ignore prosody

local setmetatable = setmetatable;
local tostring = tostring;
local t_concat = table.concat;
local s_format = string.format;
local s_lower = string.lower;
local s_upper = string.upper;
local noop = function() end;

local logger = require "prosody.util.logger";
local log = logger.init("unbound");
local net_server = require "prosody.net.server";
local libunbound = require"lunbound";
local promise = require"prosody.util.promise";
local new_id = require "prosody.util.id".short;

local gettime = require"socket".gettime;
local dns_utils = require"prosody.util.dns";
local classes, types, errors = dns_utils.classes, dns_utils.types, dns_utils.errors;
local parsers = dns_utils.parsers;

local builtin_defaults = { hoststxt = false }

local function add_defaults(conf)
	conf = conf or {};
	for option, default in pairs(builtin_defaults) do
		if conf[option] == nil then
			conf[option] = default;
		end
	end
	for option, default in pairs(libunbound.config) do
		if conf[option] == nil then
			conf[option] = default;
		end
	end
	return conf;
end

local unbound_config;
if prosody then
	local config = require"prosody.core.configmanager";
	unbound_config = add_defaults(config.get("*", "unbound"));
	prosody.events.add_handler("config-reloaded", function()
		unbound_config = add_defaults(config.get("*", "unbound"));
	end);
end
-- Note: libunbound will default to using root hints if resolvconf is unset

local function connect_server(unbound, server)
	log("debug", "Setting up net.server event handling for %s", unbound);
	return server.watchfd(unbound, function ()
		log("debug", "Processing queries for %s", unbound);
		unbound:process()
	end);
end

local unbound, server_conn;

local function initialize()
	unbound = libunbound.new(unbound_config);
	server_conn = connect_server(unbound, net_server);
end
if prosody then
	prosody.events.add_handler("server-started", initialize);
end

local answer_mt = {
	__tostring = function(self)
		if self._string then return self._string end
		local h = s_format("Status: %s", errors[self.status]);
		if self.secure then
			h = h .. ", Secure";
		elseif self.bogus then
			h = h .. s_format(", Bogus: %s", self.bogus);
		end
		local t = { h };
		for i = 1, #self do
			t[i+1]=self.qname.."\t"..classes[self.qclass].."\t"..types[self.qtype].."\t"..tostring(self[i]);
		end
		local _string = t_concat(t, "\n");
		self._string = _string;
		return _string;
	end;
};

local waiting_queries = {};

local function prep_answer(a)
	if not a then return end
	local status = errors[a.rcode];
	local qclass = classes[a.qclass];
	local qtype = types[a.qtype];
	a.status, a.class, a.type = status, qclass, qtype;

	local t = s_lower(qtype);
	local rr_mt = { __index = a, __tostring = function(self) return tostring(self[t]) end };
	local parser = parsers[qtype];
	for i = 1, #a do
		if a.bogus then
			-- Discard bogus data
			a[i] = nil;
		else
			a[i] = setmetatable({[t] = parser(a[i])}, rr_mt);
		end
	end
	return setmetatable(a, answer_mt);
end

local function lookup(callback, qname, qtype, qclass)
	if not unbound then initialize(); end
	qtype = qtype and s_upper(qtype) or "A";
	qclass = qclass and s_upper(qclass) or "IN";
	local ntype, nclass = types[qtype], classes[qclass];
	local startedat = gettime();
	local ret;
	local log_query = logger.init("unbound.query"..new_id());
	local function callback_wrapper(a, err)
		local gotdataat = gettime();
		waiting_queries[ret] = nil;
		if a then
			prep_answer(a);
			log_query("debug", "Results for %s %s %s: %s (%s, %f sec)", qname, qclass, qtype, a.rcode == 0 and (#a .. " items") or a.status,
				a.secure and "Secure" or a.bogus or "Insecure", gotdataat - startedat); -- Insecure as in unsigned
		else
			log_query("error", "Results for %s %s %s: %s", qname, qclass, qtype, tostring(err));
		end
		local ok, cerr = pcall(callback, a, err);
		if not ok then log_query("error", "Error in callback: %s", cerr); end
	end
	log_query("debug", "Resolve %s %s %s", qname, qclass, qtype);
	local err;
	ret, err = unbound:resolve_async(callback_wrapper, qname, ntype, nclass);
	if ret then
		waiting_queries[ret] = callback;
	else
		log_query("error", "Resolver error: %s", err);
	end
	return ret, err;
end

local function lookup_sync(qname, qtype, qclass)
	if not unbound then initialize(); end
	qtype = qtype and s_upper(qtype) or "A";
	qclass = qclass and s_upper(qclass) or "IN";
	local ntype, nclass = types[qtype], classes[qclass];
	local a, err = unbound:resolve(qname, ntype, nclass);
	if not a then return a, err; end
	return prep_answer(a);
end

local function cancel(id)
	local cb = waiting_queries[id];
	unbound:cancel(id);
	if cb then
		cb(nil, "canceled");
		waiting_queries[id] = nil;
	end
	return true;
end

-- Reinitiate libunbound context, drops cache
local function purge()
	for id in pairs(waiting_queries) do cancel(id); end
	if server_conn then server_conn:close(); end
	initialize();
	return true;
end

local function not_implemented()
	error "not implemented";
end
-- Public API
local _M = {
	lookup = lookup;
	cancel = cancel;
	new_async_socket = not_implemented;
	dns = {
		lookup = lookup_sync;
		cancel = cancel;
		cache = noop;
		socket_wrapper_set = noop;
		settimeout = noop;
		query = noop;
		purge = purge;
		random = noop;
		peek = noop;

		types = types;
		classes = classes;
	};
};

local function lookup_promise(_, qname, qtype, qclass)
	return promise.new(function (resolve, reject)
		local function callback(answer, err)
			if err then
				return reject(err);
			else
				return resolve(answer);
			end
		end
		local ret, err = lookup(callback, qname, qtype, qclass)
		if not ret then reject(err); end
	end);
end

local wrapper = {
	lookup = function (_, callback, qname, qtype, qclass)
		return lookup(callback, qname, qtype, qclass)
	end;
	lookup_promise = lookup_promise;
	_resolver = {
		settimeout = function () end;
		closeall = function () end;
	};
}

function _M.resolver() return wrapper; end

return _M;