File

net/resolvers/basic.lua @ 12319:8fc3c06f922d

prosodyctl: check dns: List discovered addresses for diagnostic purposes It is very common to get the "unknown address" warning with this command, but people do not always understand it, or know how to debug it. Now we clearly show the addresses that prosodyctl discovered.
author Matthew Wild <mwild1@gmail.com>
date Wed, 02 Mar 2022 16:02:42 +0000
parent 12129:7a68d5828f3b
child 12408:acfc51b9530c
line wrap: on
line source

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
		self.last_error = "hostname failed IDNA";
		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, err)
			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
				if answer.bogus then
					self.last_error = "Validation error in A lookup";
				elseif answer.status then
					self.last_error = answer.status .. " in A lookup";
				end
			else
				self.last_error = err;
			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, err)
			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
				if answer.bogus then
					self.last_error = "Validation error in AAAA lookup";
				elseif answer.status then
					self.last_error = answer.status .. " in AAAA lookup";
				end
			else
				self.last_error = err;
			end
			ready();
		end, self.hostname, "AAAA", "IN");
	else
		ready();
	end

	if self.extra and self.extra.use_dane == true then
		dns_resolver:lookup(function (answer, err)
			if answer then
				secure = secure and answer.secure;
				for _, record in ipairs(answer) do
					table.insert(tlsa, record.tlsa);
				end
				if answer.bogus then
					self.last_error = "Validation error in TLSA lookup";
				elseif answer.status then
					self.last_error = answer.status .. " in TLSA lookup";
				end
			else
				self.last_error = err;
			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;
};