File

mod_dnsupdate/mod_dnsupdate.lua @ 6254:b6e390a97c85

mod_dnsupdate: Improve handling of existing DNS records Previously it would print the final service denial record when the current DNS setup matched the config and no changes were necessary.
author Kim Alvefur <zash@zash.se>
date Mon, 12 May 2025 12:15:10 +0200
parent 5711:429be658c0bb
child 6255:52e239aa96af
line wrap: on
line source

module:set_global();

local config = require "core.configmanager";
local argparse = require "util.argparse";
local dns = require"net.adns".resolver();
local async = require "util.async";
local set = require "util.set";
local nameprep = require"util.encodings".stringprep.nameprep;
local idna_to_ascii = require"util.encodings".idna.to_ascii;

local virtualhost_services = { "xmpp-client"; "xmpps-client"; "xmpp-server"; "xmpps-server" }
local component_services = { "xmpp-server"; "xmpps-server" }

local function validate_dnsname_option(options, option_name, default)
	local host = options[option_name];
	if host == nil then return default end
	local normalized = nameprep(host);
	if not normalized then
		module:log("error", "--%s %q fails normalization");
		return;
	end
	local alabel = idna_to_ascii(normalized);
	if not alabel then
		module:log("error", "--%s %q fails IDNA");
		return;
	end
	return alabel;
end

function module.command(arg)
	local opts = argparse.parse(arg, {
		short_params = { d = "domain"; p = "primary"; t = "target"; l = "ttl"; h = "help"; ["?"] = "help" };
		value_params = { domain = true; primary = true; target = true; ttl = true };
	});

	if not arg[1] or arg[2] or not opts or opts.help or not opts.domain then
		local out = opts.help and io.stdout or io.stderr;
		out:write("prosodyctl mod_dnsupdate [options] virtualhost\n");
		out:write("\t-d --domain\tbase domain name *required*\n");
		out:write("\t-p --primary\tprimary DNS name server\n");
		out:write("\t-t --target\ttarget hostname for SRV\n");
		out:write("\t-l --ttl\tTTL to use\n");
		out:write("\t--each\tremove and replace individual SRV records\n");
		out:write("\t--reset\tremove and replace all SRV records\n");
		out:write("\t--remove\tremove all SRV records\n");
		return opts and opts.help and 0 or 1;
	end

	local vhost = nameprep(arg[1]); -- TODO loop over arg[]?
	if not vhost then
		module:log("error", "Host %q fails normalization", arg[1]);
		return 1;
	end
	local ihost = idna_to_ascii(vhost);
	if not ihost then
		module:log("error", "Host %q fails IDNA", vhost);
		return 1;
	end
	local is_component = config.get(vhost, "component_module");
	if not is_component and not config.get(vhost, "defined") then
		module:log("error", "Host %q is not defined in the config", vhost);
		return 1;
	end

	local services = virtualhost_services;
	if is_component then services = component_services; end

	local domain = validate_dnsname_option(opts, "domain");
	if not domain then
		module:log("error", "--domain is required");
		return 1;
	end
	local primary = validate_dnsname_option(opts, "primary")
		or async.wait_for(dns:lookup_promise(domain, "SOA"):next(function(ret) return ret[1].soa.mname; end));
	if not primary then
		module:log("error", "Could not discover primary name server, specify it with --primary");
		return 1;
	end
	local target = validate_dnsname_option(opts, "target", module:context(vhost):get_option_string("xmpp_host", ihost));
	-- TODO validate that target has A/AAAA

	local configured_ports = {
		["xmpp-client"] = module:get_option_array("c2s_ports", { 5222 });
		["xmpp-server"] = module:get_option_array("s2s_ports", { 5269 });
		["xmpps-client"] = module:get_option_array("c2s_direct_tls_ports", {});
		["xmpps-server"] = module:get_option_array("s2s_direct_tls_ports", {});
	};

	if opts.multiplex then
		for opt, ports in pairs(configured_ports) do
			ports:append(module:get_option_array(opt:sub(1, 5) == "xmpps" and "ssl_ports" or "ports", {}));
		end
	end

	local existing_srv = {};
	for _, service in ipairs(services) do
		existing_srv[service] = dns:lookup_promise(("_%s._tcp.%s"):format(service, ihost), "SRV");
	end

	print("zone", domain);
	print("server", primary);
	print("ttl " .. tostring(opts.ttl or 60 * 60));

	for _, service in ipairs(services) do
		local config_ports = set.new(configured_ports[service]);
		local dns_ports = set.new();

		if (opts.reset or opts.remove) and not opts.each then
			print(("del _%s._tcp.%s IN SRV"):format(service, ihost));
		else
			local records = (async.wait_for(existing_srv[service]));
			for _, rr in ipairs(records) do
				if target == nameprep(rr.srv.target):gsub("%.$", "") then
					dns_ports:add(rr.srv.port)
				elseif opts.each then
					print(("del _%s._tcp.%s IN SRV %s"):format(service, ihost, rr));
				end
			end
		end

		if not opts.remove then
			if config_ports:empty() then
				print(("add _%s._tcp.%s IN SRV 0 0 0 ."):format(service, ihost));
			else
				for port in (config_ports - dns_ports) do
					print(("add _%s._tcp.%s IN SRV 1 1 %d %s"):format(service, ihost, port, target));
				end
			end
		end
	end

	print("show");
	print("send");
	print("answer");
end