File

+
−local adns = require "prosody.net.adns";
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−local inet_pton = require "prosody.util.net".pton;
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−local inet_ntop = require "prosody.util.net".ntop;
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−local idna_to_ascii = require "prosody.util.encodings".idna.to_ascii;
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−local promise = require "prosody.util.promise";
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−local t_move = require "prosody.util.table".move;
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−
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−local methods = {};
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−local resolver_mt = { __index = methods };
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−
+
−-- FIXME RFC 6724
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−
+
−local function do_dns_lookup(self, dns_resolver, record_type, name, allow_insecure)
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−	return promise.new(function (resolve, reject)
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−		local ipv = (record_type == "A" and "4") or (record_type == "AAAA" and "6") or nil;
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−		if ipv and self.extra["use_ipv"..ipv] == false then
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−			return reject(("IPv%s disabled - %s lookup skipped"):format(ipv, record_type));
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−		elseif record_type == "TLSA" and self.extra.use_dane ~= true then
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−			return reject("DANE disabled - TLSA lookup skipped");
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−		end
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−		dns_resolver:lookup(function (answer, err)
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−			if not answer then
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−				return reject(err);
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−			elseif answer.bogus then
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−				return reject(("Validation error in %s lookup"):format(record_type));
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−			elseif not (answer.secure or allow_insecure) then
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−				return reject(("Insecure response in %s lookup"):format(record_type));
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−			elseif answer.status and #answer == 0 then
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−				return reject(("%s in %s lookup"):format(answer.status, record_type));
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−			end
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−
+
−			local targets = { secure = answer.secure };
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−			for _, record in ipairs(answer) do
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−				if ipv then
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−					table.insert(targets, { self.conn_type..ipv, record[record_type:lower()], self.port, self.extra });
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−				else
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−					table.insert(targets, record[record_type:lower()]);
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−				end
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−			end
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−			return resolve(targets);
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−		end, name, record_type, "IN");
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−	end);
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−end
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−
+
−local function merge_targets(ipv4_targets, ipv6_targets)
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−	local result = { secure = ipv4_targets.secure and ipv6_targets.secure };
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−	local common_length = math.min(#ipv4_targets, #ipv6_targets);
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−	for i = 1, common_length do
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−		table.insert(result, ipv6_targets[i]);
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−		table.insert(result, ipv4_targets[i]);
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−	end
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−	if common_length < #ipv4_targets then
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−		t_move(ipv4_targets, common_length+1, #ipv4_targets, common_length+1, result);
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−	elseif common_length < #ipv6_targets then
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−		t_move(ipv6_targets, common_length+1, #ipv6_targets, common_length+1, result);
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−	end
+
−	return result;
+
−end
+
−
+
−-- Find the next target to connect to, and
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−-- pass it to cb()
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−function methods:next(cb)
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−	if self.targets then
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−		if #self.targets == 0 then
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−			cb(nil);
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−			return;
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−		end
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−		local next_target = table.remove(self.targets, 1);
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−		cb(next_target[1], next_target[2], next_target[3], next_target[4], not not self.targets[1]);
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−		return;
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−	end
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−
+
−	if not self.hostname then
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−		self.last_error = "hostname failed IDNA";
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−		cb(nil);
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−		return;
+
−	end
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−
+
−	-- Resolve DNS to target list
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−	local dns_resolver = adns.resolver();
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−
+
−	local dns_lookups = {
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−		ipv4 = do_dns_lookup(self, dns_resolver, "A", self.hostname, true);
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−		ipv6 = do_dns_lookup(self, dns_resolver, "AAAA", self.hostname, true);
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−		tlsa = do_dns_lookup(self, dns_resolver, "TLSA", ("_%d._%s.%s"):format(self.port, self.conn_type, self.hostname));
+
−	};
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−
+
−	promise.all_settled(dns_lookups):next(function (dns_results)
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−		-- Combine targets, assign to self.targets, self:next(cb)
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−		local have_ipv4 = dns_results.ipv4.status == "fulfilled";
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−		local have_ipv6 = dns_results.ipv6.status == "fulfilled";
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−
+
−		if have_ipv4 and have_ipv6 then
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−			self.targets = merge_targets(dns_results.ipv4.value, dns_results.ipv6.value);
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−		elseif have_ipv4 then
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−			self.targets = dns_results.ipv4.value;
+
−		elseif have_ipv6 then
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−			self.targets = dns_results.ipv6.value;
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−		else
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−			self.targets = {};
+
−		end
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−
+
−		if self.extra and self.extra.use_dane then
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−			if self.targets.secure and dns_results.tlsa.status == "fulfilled" then
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−				self.extra.tlsa = dns_results.tlsa.value;
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−				self.extra.dane_hostname = self.hostname;
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−			else
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−				self.extra.tlsa = nil;
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−				self.extra.dane_hostname = nil;
+
−			end
+
−		elseif self.extra and self.extra.srv_secure then
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−			self.extra.secure_hostname = self.hostname;
+
−		end
+
−
+
−		self:next(cb);
+
−	end):catch(function (err)
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−		self.last_error = err;
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−		self.targets = {};
+
−	end);
+
−end
+
−
+
−local function new(hostname, port, conn_type, extra)
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−	local ascii_host = idna_to_ascii(hostname);
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−	local targets = nil;
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−	conn_type = conn_type or "tcp";
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−
+
−	local is_ip = inet_pton(hostname);
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−	if not is_ip and hostname:sub(1,1) == '[' then
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−		is_ip = inet_pton(hostname:sub(2,-2));
+
−	end
+
−	if is_ip then
+
−		hostname = inet_ntop(is_ip);
+
−		if #is_ip == 16 then
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−			targets = { { conn_type.."6", hostname, port, extra } };
+
−		elseif #is_ip == 4 then
+
−			targets = { { conn_type.."4", hostname, port, extra } };
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−		end
+
−	end
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−
+
−	return setmetatable({
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−		hostname = ascii_host;
+
−		port = port;
+
−		conn_type = conn_type;
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−		extra = extra or {};
+
−		targets = targets;
+
−	}, resolver_mt);
+
−end
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−
+
−return {
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−	new = new;
+
−};