prosody
92f30e8ecdfc
net/unbound.lua

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net/unbound.lua @ 10962:92f30e8ecdfc

net.unbound: Async DNS resolver library based on libunbound via luaunbound
author Kim Alvefur <zash@zash.se>
date Sat, 09 Mar 2019 21:19:24 +0100
child 10967:67aabf83230b
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10961:f93dce30089a 10962:92f30e8ecdfc
1 -- libunbound based net.adns replacement for Prosody IM
2 -- Copyright (C) 2013-2015 Kim Alvefur
3 --
4 -- This file is MIT licensed.
5 --
6 -- luacheck: ignore prosody
7
8 local setmetatable = setmetatable;
9 local tostring = tostring;
10 local t_concat = table.concat;
11 local s_format = string.format;
12 local s_lower = string.lower;
13 local s_upper = string.upper;
14 local noop = function() end;
15 local zero = function() return 0 end;
16 local truop = function() return true; end;
17
18 local log = require "util.logger".init("unbound");
19 local net_server = require "net.server";
20 local libunbound = require"lunbound";
21 local have_promise, promise = pcall(require, "util.promise");
22
23 local gettime = require"socket".gettime;
24 local dns_utils = require"util.dns";
25 local classes, types, errors = dns_utils.classes, dns_utils.types, dns_utils.errors;
26 local parsers = dns_utils.parsers;
27
28 local function add_defaults(conf)
29 if conf then
30 for option, default in pairs(libunbound.config) do
31 if conf[option] == nil then
32 conf[option] = default;
33 end
34 end
35 end
36 return conf;
37 end
38
39 local unbound_config;
40 if prosody then
41 local config = require"core.configmanager";
42 unbound_config = add_defaults(config.get("*", "unbound"));
43 prosody.events.add_handler("config-reloaded", function()
44 unbound_config = add_defaults(config.get("*", "unbound"));
45 end);
46 end
47 -- Note: libunbound will default to using root hints if resolvconf is unset
48
49 local function connect_server(unbound, server)
50 if server.watchfd then
51 return server.watchfd(unbound, function ()
52 unbound:process()
53 end);
54 elseif server.event and server.addevent then
55 local EV_READ = server.event.EV_READ;
56 local function event_callback()
57 unbound:process();
58 return EV_READ;
59 end
60 return server.addevent(unbound:getfd(), EV_READ, event_callback)
61 elseif server.wrapclient then
62 local conn = {
63 getfd = function()
64 return unbound:getfd();
65 end,
66
67 send = zero,
68 receive = noop,
69 settimeout = noop,
70 close = truop,
71 }
72
73 local function process()
74 unbound:process();
75 end
76 local listener = {
77 onincoming = process,
78
79 onconnect = noop,
80 ondisconnect = noop,
81 onreadtimeout = truop,
82 };
83 return server.wrapclient(conn, "dns", 0, listener, "*a" );
84 end
85 end
86
87 local unbound = libunbound.new(unbound_config);
88
89 local server_conn = connect_server(unbound, net_server);
90
91 local answer_mt = {
92 __tostring = function(self)
93 if self._string then return self._string end
94 local h = s_format("Status: %s", errors[self.status]);
95 if self.secure then
96 h = h .. ", Secure";
97 elseif self.bogus then
98 h = h .. s_format(", Bogus: %s", self.bogus);
99 end
100 local t = { h };
101 for i = 1, #self do
102 t[i+1]=self.qname.."\t"..classes[self.qclass].."\t"..types[self.qtype].."\t"..tostring(self[i]);
103 end
104 local _string = t_concat(t, "\n");
105 self._string = _string;
106 return _string;
107 end;
108 };
109
110 local waiting_queries = {};
111
112 local function prep_answer(a)
113 if not a then return end
114 local status = errors[a.rcode];
115 local qclass = classes[a.qclass];
116 local qtype = types[a.qtype];
117 a.status, a.class, a.type = status, qclass, qtype;
118
119 local t = s_lower(qtype);
120 local rr_mt = { __index = a, __tostring = function(self) return tostring(self[t]) end };
121 local parser = parsers[qtype];
122 for i = 1, #a do
123 if a.bogus then
124 -- Discard bogus data
125 a[i] = nil;
126 else
127 a[i] = setmetatable({[t] = parser(a[i])}, rr_mt);
128 end
129 end
130 return setmetatable(a, answer_mt);
131 end
132
133 local function lookup(callback, qname, qtype, qclass)
134 qtype = qtype and s_upper(qtype) or "A";
135 qclass = qclass and s_upper(qclass) or "IN";
136 local ntype, nclass = types[qtype], classes[qclass];
137 local startedat = gettime();
138 local ret;
139 local function callback_wrapper(a, err)
140 local gotdataat = gettime();
141 waiting_queries[ret] = nil;
142 if a then
143 prep_answer(a);
144 log("debug", "Results for %s %s %s: %s (%s, %f sec)", qname, qclass, qtype, a.rcode == 0 and (#a .. " items") or a.status,
145 a.secure and "Secure" or a.bogus or "Insecure", gotdataat - startedat); -- Insecure as in unsigned
146 else
147 log("error", "Results for %s %s %s: %s", qname, qclass, qtype, tostring(err));
148 end
149 local ok, cerr = pcall(callback, a, err);
150 if not ok then log("error", "Error in callback: %s", cerr); end
151 end
152 log("debug", "Resolve %s %s %s", qname, qclass, qtype);
153 local err;
154 ret, err = unbound:resolve_async(callback_wrapper, qname, ntype, nclass);
155 if ret then
156 waiting_queries[ret] = callback;
157 else
158 log("warn", err);
159 end
160 return ret, err;
161 end
162
163 local function lookup_sync(qname, qtype, qclass)
164 qtype = qtype and s_upper(qtype) or "A";
165 qclass = qclass and s_upper(qclass) or "IN";
166 local ntype, nclass = types[qtype], classes[qclass];
167 local a, err = unbound:resolve(qname, ntype, nclass);
168 if not a then return a, err; end
169 return prep_answer(a);
170 end
171
172 local function cancel(id)
173 local cb = waiting_queries[id];
174 unbound:cancel(id);
175 if cb then
176 cb(nil, "canceled");
177 waiting_queries[id] = nil;
178 end
179 return true;
180 end
181
182 -- Reinitiate libunbound context, drops cache
183 local function purge()
184 for id in pairs(waiting_queries) do cancel(id); end
185 if server_conn then server_conn:close(); end
186 unbound = libunbound.new(unbound_config);
187 server_conn = connect_server(unbound, net_server);
188 return true;
189 end
190
191 local function not_implemented()
192 error "not implemented";
193 end
194 -- Public API
195 local _M = {
196 lookup = lookup;
197 cancel = cancel;
198 new_async_socket = not_implemented;
199 dns = {
200 lookup = lookup_sync;
201 cancel = cancel;
202 cache = noop;
203 socket_wrapper_set = noop;
204 settimeout = noop;
205 query = noop;
206 purge = purge;
207 random = noop;
208 peek = noop;
209
210 types = types;
211 classes = classes;
212 };
213 };
214
215 local lookup_promise;
216 if have_promise then
217 function lookup_promise(_, qname, qtype, qclass)
218 return promise.new(function (resolve, reject)
219 local function callback(answer, err)
220 if err then
221 return reject(err);
222 else
223 return resolve(answer);
224 end
225 end
226 local ret, err = lookup(callback, qname, qtype, qclass)
227 if not ret then reject(err); end
228 end);
229 end
230 end
231
232 local wrapper = {
233 lookup = function (_, callback, qname, qtype, qclass)
234 return lookup(callback, qname, qtype, qclass)
235 end;
236 lookup_promise = lookup_promise;
237 _resolver = {
238 settimeout = function () end;
239 closeall = function () end;
240 };
241 }
242
243 function _M.resolver() return wrapper; end
244
245 return _M;