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authorKim Alvefur <zash@zash.se>2019-03-09 21:19:24 +0100
committerKim Alvefur <zash@zash.se>2019-03-09 21:19:24 +0100
commitb96535b6ae01148fe9969fffd5e602798aa1cdcc (patch)
tree0ba3a2d8652c215161b60fca9b6e87ecd20dde64
parent49dd598e71d066441f44a21f86a755c959bdcbf3 (diff)
downloadprosody-b96535b6ae01148fe9969fffd5e602798aa1cdcc.tar.gz
prosody-b96535b6ae01148fe9969fffd5e602798aa1cdcc.zip
net.unbound: Async DNS resolver library based on libunbound via luaunbound
-rw-r--r--net/unbound.lua245
1 files changed, 245 insertions, 0 deletions
diff --git a/net/unbound.lua b/net/unbound.lua
new file mode 100644
index 00000000..df26cd36
--- /dev/null
+++ b/net/unbound.lua
@@ -0,0 +1,245 @@
+-- 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 zero = function() return 0 end;
+local truop = function() return true; end;
+
+local log = require "util.logger".init("unbound");
+local net_server = require "net.server";
+local libunbound = require"lunbound";
+local have_promise, promise = pcall(require, "util.promise");
+
+local gettime = require"socket".gettime;
+local dns_utils = require"util.dns";
+local classes, types, errors = dns_utils.classes, dns_utils.types, dns_utils.errors;
+local parsers = dns_utils.parsers;
+
+local function add_defaults(conf)
+ if conf then
+ for option, default in pairs(libunbound.config) do
+ if conf[option] == nil then
+ conf[option] = default;
+ end
+ end
+ end
+ return conf;
+end
+
+local unbound_config;
+if prosody then
+ local config = require"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)
+ if server.watchfd then
+ return server.watchfd(unbound, function ()
+ unbound:process()
+ end);
+ elseif server.event and server.addevent then
+ local EV_READ = server.event.EV_READ;
+ local function event_callback()
+ unbound:process();
+ return EV_READ;
+ end
+ return server.addevent(unbound:getfd(), EV_READ, event_callback)
+ elseif server.wrapclient then
+ local conn = {
+ getfd = function()
+ return unbound:getfd();
+ end,
+
+ send = zero,
+ receive = noop,
+ settimeout = noop,
+ close = truop,
+ }
+
+ local function process()
+ unbound:process();
+ end
+ local listener = {
+ onincoming = process,
+
+ onconnect = noop,
+ ondisconnect = noop,
+ onreadtimeout = truop,
+ };
+ return server.wrapclient(conn, "dns", 0, listener, "*a" );
+ end
+end
+
+local unbound = libunbound.new(unbound_config);
+
+local server_conn = connect_server(unbound, net_server);
+
+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)
+ 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 function callback_wrapper(a, err)
+ local gotdataat = gettime();
+ waiting_queries[ret] = nil;
+ if a then
+ prep_answer(a);
+ log("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("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("error", "Error in callback: %s", cerr); end
+ end
+ log("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("warn", err);
+ end
+ return ret, err;
+end
+
+local function lookup_sync(qname, qtype, qclass)
+ 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
+ unbound = libunbound.new(unbound_config);
+ server_conn = connect_server(unbound, net_server);
+ 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 lookup_promise;
+if have_promise then
+ 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
+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;