File

net/resolvers/service.lua @ 11430:56a282ecdcf1

net.resolvers.basic: Fix completion condition when IPv6 is disabled Fixes mistake introduced in 5a71f14ab77c that made it so this ready() newer got called and thus it would be stuck waiting for it. Looks like the kind of thing that could have been introduced by a merge or rebase. Thanks MattJ
author Kim Alvefur <zash@zash.se>
date Mon, 15 Mar 2021 23:09:42 +0100
parent 10970:4603697aee50
child 11710:26a8cc9d9eb7
line wrap: on
line source

local adns = require "net.adns";
local basic = require "net.resolvers.basic";
local inet_pton = require "util.net".pton;
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 };

-- Find the next target to connect to, and
-- pass it to cb()
function methods:next(cb)
	if self.targets then
		if not self.resolver then
			if #self.targets == 0 then
				cb(nil);
				return;
			end
			local next_target = table.remove(self.targets, 1);
			self.resolver = basic.new(unpack(next_target, 1, 4));
		end
		self.resolver:next(function (...)
			if ... == nil then
				self.resolver = nil;
				self:next(cb);
			else
				cb(...);
			end
		end);
		return;
	end

	if not self.hostname then
		-- FIXME report IDNA error
		cb(nil);
		return;
	end

	local targets = {};
	local function ready()
		self.targets = targets;
		self:next(cb);
	end

	-- Resolve DNS to target list
	local dns_resolver = adns.resolver();
	dns_resolver:lookup(function (answer, err)
		if not answer and not err then
			-- net.adns returns nil if there are zero records or nxdomain
			answer = {};
		end
		if answer then
			if #answer == 0 then
				if self.extra and self.extra.default_port then
					table.insert(targets, { self.hostname, self.extra.default_port, self.conn_type, self.extra });
				end
				ready();
				return;
			end

			if #answer == 1 and answer[1].srv.target == "." then -- No service here
				ready();
				return;
			end

			table.sort(answer, function (a, b) return a.srv.priority < b.srv.priority end);
			for _, record in ipairs(answer) do
				table.insert(targets, { record.srv.target, record.srv.port, self.conn_type, self.extra });
			end
		end
		ready();
	end, "_" .. self.service .. "._" .. self.conn_type .. "." .. self.hostname, "SRV", "IN");
end

local function new(hostname, service, conn_type, extra)
	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 and extra and extra.default_port then
		return basic.new(hostname, extra.default_port, conn_type, extra);
	end

	return setmetatable({
		hostname = idna_to_ascii(hostname);
		service = service;
		conn_type = conn_type or "tcp";
		extra = extra;
	}, resolver_mt);
end

return {
	new = new;
};