2 -- This file is included with Prosody IM. It has modifications,
3 -- which are hereby placed in the public domain.
6 -- todo: quick (default) header generation
7 -- todo: nxdomain, error handling
8 -- todo: cache results of encodeName
11 -- reference: http://tools.ietf.org/html/rfc1035
12 -- reference: http://tools.ietf.org/html/rfc1876 (LOC)
15 local socket = require "socket";
16 local timer = require "util.timer";
18 local _, windows = pcall(require, "util.windows");
19 local is_windows = (_ and windows) or os.getenv("WINDIR");
21 local coroutine, io, math, string, table =
22 coroutine, io, math, string, table;
24 local ipairs, next, pairs, print, setmetatable, tostring, assert, error, unpack, select =
25 ipairs, next, pairs, print, setmetatable, tostring, assert, error, unpack, select;
27 local ztact = { -- public domain 20080404 lua@ztact.com
28 get = function(parent, ...)
29 local len = select('#', ...);
31 parent = parent[select(i, ...)];
32 if parent == nil then break; end
36 set = function(parent, ...)
37 local len = select('#', ...);
38 local key, value = select(len-1, ...);
39 local cutpoint, cutkey;
42 local key = select (i, ...)
43 local child = parent[key]
48 elseif next(child, next(child)) then
49 cutpoint = nil; cutkey = nil;
50 elseif cutpoint == nil then
51 cutpoint = parent; cutkey = key;
53 elseif child == nil then
60 if value == nil and cutpoint then
61 cutpoint[cutkey] = nil;
68 local get, set = ztact.get, ztact.set;
70 local default_timeout = 15;
72 -------------------------------------------------- module dns
77 -- dns type & class codes ------------------------------ dns type & class codes
80 local append = table.insert
83 local function highbyte(i) -- - - - - - - - - - - - - - - - - - - highbyte
84 return (i-(i%0x100))/0x100;
88 local function augment (t) -- - - - - - - - - - - - - - - - - - - - augment
90 for i,s in pairs(t) do
93 a[string.lower(s)] = s;
99 local function encode (t) -- - - - - - - - - - - - - - - - - - - - - encode
101 for i,s in pairs(t) do
102 local word = string.char(highbyte(i), i%0x100);
105 code[string.lower(s)] = word;
112 'A', 'NS', 'MD', 'MF', 'CNAME', 'SOA', 'MB', 'MG', 'MR', 'NULL', 'WKS',
113 'PTR', 'HINFO', 'MINFO', 'MX', 'TXT',
114 [ 28] = 'AAAA', [ 29] = 'LOC', [ 33] = 'SRV',
115 [252] = 'AXFR', [253] = 'MAILB', [254] = 'MAILA', [255] = '*' };
118 dns.classes = { 'IN', 'CS', 'CH', 'HS', [255] = '*' };
121 dns.type = augment (dns.types);
122 dns.class = augment (dns.classes);
123 dns.typecode = encode (dns.types);
124 dns.classcode = encode (dns.classes);
128 local function standardize(qname, qtype, qclass) -- - - - - - - standardize
129 if string.byte(qname, -1) ~= 0x2E then qname = qname..'.'; end
130 qname = string.lower(qname);
131 return qname, dns.type[qtype or 'A'], dns.class[qclass or 'IN'];
135 local function prune(rrs, time, soft) -- - - - - - - - - - - - - - - prune
136 time = time or socket.gettime();
137 for i,rr in pairs(rrs) do
139 -- rr.tod = rr.tod - 50 -- accelerated decripitude
140 rr.ttl = math.floor(rr.tod - time);
142 table.remove(rrs, i);
143 return prune(rrs, time, soft); -- Re-iterate
145 elseif soft == 'soft' then -- What is this? I forget!
153 -- metatables & co. ------------------------------------------ metatables & co.
157 resolver.__index = resolver;
159 resolver.timeout = default_timeout;
164 local rr_metatable = {}; -- - - - - - - - - - - - - - - - - - - rr_metatable
165 function rr_metatable.__tostring(rr)
166 local s0 = string.format('%2s %-5s %6i %-28s', rr.class, rr.type, rr.ttl, rr.name);
168 if rr.type == 'A' then
170 elseif rr.type == 'MX' then
171 s1 = string.format(' %2i %s', rr.pref, rr.mx);
172 elseif rr.type == 'CNAME' then
174 elseif rr.type == 'LOC' then
175 s1 = ' '..resolver.LOC_tostring(rr);
176 elseif rr.type == 'NS' then
178 elseif rr.type == 'SRV' then
179 s1 = ' '..SRV_tostring(rr);
180 elseif rr.type == 'TXT' then
183 s1 = ' <UNKNOWN RDATA TYPE>';
189 local rrs_metatable = {}; -- - - - - - - - - - - - - - - - - - rrs_metatable
190 function rrs_metatable.__tostring(rrs)
192 for i,rr in pairs(rrs) do
193 append(t, tostring(rr)..'\n');
195 return table.concat(t);
199 local cache_metatable = {}; -- - - - - - - - - - - - - - - - cache_metatable
200 function cache_metatable.__tostring(cache)
201 local time = socket.gettime();
203 for class,types in pairs(cache) do
204 for type,names in pairs(types) do
205 for name,rrs in pairs(names) do
207 append(t, tostring(rrs));
211 return table.concat(t);
215 function resolver:new() -- - - - - - - - - - - - - - - - - - - - - resolver
216 local r = { active = {}, cache = {}, unsorted = {} };
217 setmetatable(r, resolver);
218 setmetatable(r.cache, cache_metatable);
219 setmetatable(r.unsorted, { __mode = 'kv' });
224 -- packet layer -------------------------------------------------- packet layer
227 function dns.random(...) -- - - - - - - - - - - - - - - - - - - dns.random
228 math.randomseed(math.floor(10000*socket.gettime()));
229 dns.random = math.random;
230 return dns.random(...);
234 local function encodeHeader(o) -- - - - - - - - - - - - - - - encodeHeader
236 o.id = o.id or dns.random(0, 0xffff); -- 16b (random) id
238 o.rd = o.rd or 1; -- 1b 1 recursion desired
239 o.tc = o.tc or 0; -- 1b 1 truncated response
240 o.aa = o.aa or 0; -- 1b 1 authoritative response
241 o.opcode = o.opcode or 0; -- 4b 0 query
243 -- 2 server status request
245 o.qr = o.qr or 0; -- 1b 0 query, 1 response
247 o.rcode = o.rcode or 0; -- 4b 0 no error
254 o.z = o.z or 0; -- 3b 0 resvered
255 o.ra = o.ra or 0; -- 1b 1 recursion available
257 o.qdcount = o.qdcount or 1; -- 16b number of question RRs
258 o.ancount = o.ancount or 0; -- 16b number of answers RRs
259 o.nscount = o.nscount or 0; -- 16b number of nameservers RRs
260 o.arcount = o.arcount or 0; -- 16b number of additional RRs
262 -- string.char() rounds, so prevent roundup with -0.4999
263 local header = string.char(
264 highbyte(o.id), o.id %0x100,
265 o.rd + 2*o.tc + 4*o.aa + 8*o.opcode + 128*o.qr,
266 o.rcode + 16*o.z + 128*o.ra,
267 highbyte(o.qdcount), o.qdcount %0x100,
268 highbyte(o.ancount), o.ancount %0x100,
269 highbyte(o.nscount), o.nscount %0x100,
270 highbyte(o.arcount), o.arcount %0x100
277 local function encodeName(name) -- - - - - - - - - - - - - - - - encodeName
279 for part in string.gmatch(name, '[^.]+') do
280 append(t, string.char(string.len(part)));
283 append(t, string.char(0));
284 return table.concat(t);
288 local function encodeQuestion(qname, qtype, qclass) -- - - - encodeQuestion
289 qname = encodeName(qname);
290 qtype = dns.typecode[qtype or 'a'];
291 qclass = dns.classcode[qclass or 'in'];
292 return qname..qtype..qclass;
296 function resolver:byte(len) -- - - - - - - - - - - - - - - - - - - - - byte
298 local offset = self.offset;
299 local last = offset + len - 1;
300 if last > #self.packet then
301 error(string.format('out of bounds: %i>%i', last, #self.packet));
303 self.offset = offset + len;
304 return string.byte(self.packet, offset, last);
308 function resolver:word() -- - - - - - - - - - - - - - - - - - - - - - word
309 local b1, b2 = self:byte(2);
310 return 0x100*b1 + b2;
314 function resolver:dword () -- - - - - - - - - - - - - - - - - - - - - dword
315 local b1, b2, b3, b4 = self:byte(4);
316 --print('dword', b1, b2, b3, b4);
317 return 0x1000000*b1 + 0x10000*b2 + 0x100*b3 + b4;
321 function resolver:sub(len) -- - - - - - - - - - - - - - - - - - - - - - sub
323 local s = string.sub(self.packet, self.offset, self.offset + len - 1);
324 self.offset = self.offset + len;
329 function resolver:header(force) -- - - - - - - - - - - - - - - - - - header
330 local id = self:word();
331 --print(string.format(':header id %x', id));
332 if not self.active[id] and not force then return nil; end
334 local h = { id = id };
336 local b1, b2 = self:byte(2);
348 h.qdcount = self:word();
349 h.ancount = self:word();
350 h.nscount = self:word();
351 h.arcount = self:word();
353 for k,v in pairs(h) do h[k] = v-v%1; end
359 function resolver:name() -- - - - - - - - - - - - - - - - - - - - - - name
360 local remember, pointers = nil, 0;
361 local len = self:byte();
364 if len >= 0xc0 then -- name is "compressed"
365 pointers = pointers + 1;
366 if pointers >= 20 then error('dns error: 20 pointers'); end;
367 local offset = ((len-0xc0)*0x100) + self:byte();
368 remember = remember or self.offset;
369 self.offset = offset + 1; -- +1 for lua
370 else -- name is not compressed
371 append(n, self:sub(len)..'.');
375 self.offset = remember or self.offset;
376 return table.concat(n);
380 function resolver:question() -- - - - - - - - - - - - - - - - - - question
382 q.name = self:name();
383 q.type = dns.type[self:word()];
384 q.class = dns.class[self:word()];
389 function resolver:A(rr) -- - - - - - - - - - - - - - - - - - - - - - - - A
390 local b1, b2, b3, b4 = self:byte(4);
391 rr.a = string.format('%i.%i.%i.%i', b1, b2, b3, b4);
395 function resolver:CNAME(rr) -- - - - - - - - - - - - - - - - - - - - CNAME
396 rr.cname = self:name();
400 function resolver:MX(rr) -- - - - - - - - - - - - - - - - - - - - - - - MX
401 rr.pref = self:word();
406 function resolver:LOC_nibble_power() -- - - - - - - - - - LOC_nibble_power
407 local b = self:byte();
408 --print('nibbles', ((b-(b%0x10))/0x10), (b%0x10));
409 return ((b-(b%0x10))/0x10) * (10^(b%0x10));
413 function resolver:LOC(rr) -- - - - - - - - - - - - - - - - - - - - - - LOC
414 rr.version = self:byte();
415 if rr.version == 0 then
416 rr.loc = rr.loc or {};
417 rr.loc.size = self:LOC_nibble_power();
418 rr.loc.horiz_pre = self:LOC_nibble_power();
419 rr.loc.vert_pre = self:LOC_nibble_power();
420 rr.loc.latitude = self:dword();
421 rr.loc.longitude = self:dword();
422 rr.loc.altitude = self:dword();
427 local function LOC_tostring_degrees(f, pos, neg) -- - - - - - - - - - - - -
429 if f < 0 then pos = neg; f = -f; end
430 local deg, min, msec;
435 return string.format('%3d %2d %2.3f %s', deg, min, msec/1000, pos);
439 function resolver.LOC_tostring(rr) -- - - - - - - - - - - - - LOC_tostring
443 for k,name in pairs { 'size', 'horiz_pre', 'vert_pre', 'latitude', 'longitude', 'altitude' } do
444 append(t, string.format('%4s%-10s: %12.0f\n', '', name, rr.loc[name]));
448 append(t, string.format(
449 '%s %s %.2fm %.2fm %.2fm %.2fm',
450 LOC_tostring_degrees (rr.loc.latitude, 'N', 'S'),
451 LOC_tostring_degrees (rr.loc.longitude, 'E', 'W'),
452 (rr.loc.altitude - 10000000) / 100,
454 rr.loc.horiz_pre / 100,
455 rr.loc.vert_pre / 100
458 return table.concat(t);
462 function resolver:NS(rr) -- - - - - - - - - - - - - - - - - - - - - - - NS
467 function resolver:SOA(rr) -- - - - - - - - - - - - - - - - - - - - - - SOA
471 function resolver:SRV(rr) -- - - - - - - - - - - - - - - - - - - - - - SRV
473 rr.srv.priority = self:word();
474 rr.srv.weight = self:word();
475 rr.srv.port = self:word();
476 rr.srv.target = self:name();
479 function resolver:PTR(rr)
480 rr.ptr = self:name();
483 function SRV_tostring(rr) -- - - - - - - - - - - - - - - - - - SRV_tostring
485 return string.format( '%5d %5d %5d %s', s.priority, s.weight, s.port, s.target );
489 function resolver:TXT(rr) -- - - - - - - - - - - - - - - - - - - - - - TXT
490 rr.txt = self:sub (rr.rdlength);
494 function resolver:rr() -- - - - - - - - - - - - - - - - - - - - - - - - rr
496 setmetatable(rr, rr_metatable);
497 rr.name = self:name(self);
498 rr.type = dns.type[self:word()] or rr.type;
499 rr.class = dns.class[self:word()] or rr.class;
500 rr.ttl = 0x10000*self:word() + self:word();
501 rr.rdlength = self:word();
504 rr.tod = self.time + 30;
506 rr.tod = self.time + rr.ttl;
509 local remember = self.offset;
510 local rr_parser = self[dns.type[rr.type]];
511 if rr_parser then rr_parser(self, rr); end
512 self.offset = remember;
513 rr.rdata = self:sub(rr.rdlength);
518 function resolver:rrs (count) -- - - - - - - - - - - - - - - - - - - - - rrs
520 for i = 1,count do append(rrs, self:rr()); end
525 function resolver:decode(packet, force) -- - - - - - - - - - - - - - decode
526 self.packet, self.offset = packet, 1;
527 local header = self:header(force);
528 if not header then return nil; end
529 local response = { header = header };
531 response.question = {};
532 local offset = self.offset;
533 for i = 1,response.header.qdcount do
534 append(response.question, self:question());
536 response.question.raw = string.sub(self.packet, offset, self.offset - 1);
539 if not self.active[response.header.id] or not self.active[response.header.id][response.question.raw] then
544 response.answer = self:rrs(response.header.ancount);
545 response.authority = self:rrs(response.header.nscount);
546 response.additional = self:rrs(response.header.arcount);
552 -- socket layer -------------------------------------------------- socket layer
555 resolver.delays = { 1, 3 };
558 function resolver:addnameserver(address) -- - - - - - - - - - addnameserver
559 self.server = self.server or {};
560 append(self.server, address);
564 function resolver:setnameserver(address) -- - - - - - - - - - setnameserver
566 self:addnameserver(address);
570 function resolver:adddefaultnameservers() -- - - - - adddefaultnameservers
572 if windows and windows.get_nameservers then
573 for _, server in ipairs(windows.get_nameservers()) do
574 self:addnameserver(server);
577 if not self.server or #self.server == 0 then
578 -- TODO log warning about no nameservers, adding opendns servers as fallback
579 self:addnameserver("208.67.222.222");
580 self:addnameserver("208.67.220.220");
583 local resolv_conf = io.open("/etc/resolv.conf");
585 for line in resolv_conf:lines() do
586 line = line:gsub("#.*$", "")
587 :match('^%s*nameserver%s+(.*)%s*$');
589 line:gsub("%f[%d.](%d+%.%d+%.%d+%.%d+)%f[^%d.]", function (address)
590 self:addnameserver(address)
595 if not self.server or #self.server == 0 then
596 -- TODO log warning about no nameservers, adding localhost as the default nameserver
597 self:addnameserver("127.0.0.1");
603 function resolver:getsocket(servernum) -- - - - - - - - - - - - - getsocket
604 self.socket = self.socket or {};
605 self.socketset = self.socketset or {};
607 local sock = self.socket[servernum];
608 if sock then return sock; end
611 if self.socket_wrapper then sock = self.socket_wrapper(sock, self); end
613 -- todo: attempt to use a random port, fallback to 0
614 sock:setsockname('*', 0);
615 sock:setpeername(self.server[servernum], 53);
616 self.socket[servernum] = sock;
617 self.socketset[sock] = servernum;
621 function resolver:voidsocket(sock)
622 if self.socket[sock] then
623 self.socketset[self.socket[sock]] = nil;
624 self.socket[sock] = nil;
625 elseif self.socketset[sock] then
626 self.socket[self.socketset[sock]] = nil;
627 self.socketset[sock] = nil;
631 function resolver:socket_wrapper_set(func) -- - - - - - - socket_wrapper_set
632 self.socket_wrapper = func;
636 function resolver:closeall () -- - - - - - - - - - - - - - - - - - closeall
637 for i,sock in ipairs(self.socket) do
638 self.socket[i] = nil;
639 self.socketset[sock] = nil;
645 function resolver:remember(rr, type) -- - - - - - - - - - - - - - remember
646 --print ('remember', type, rr.class, rr.type, rr.name)
647 local qname, qtype, qclass = standardize(rr.name, rr.type, rr.class);
651 local all = get(self.cache, qclass, '*', qname);
652 --print('remember all', all);
653 if all then append(all, rr); end
656 self.cache = self.cache or setmetatable({}, cache_metatable);
657 local rrs = get(self.cache, qclass, type, qname) or
658 set(self.cache, qclass, type, qname, setmetatable({}, rrs_metatable));
661 if type == 'MX' then self.unsorted[rrs] = true; end
665 local function comp_mx(a, b) -- - - - - - - - - - - - - - - - - - - comp_mx
666 return (a.pref == b.pref) and (a.mx < b.mx) or (a.pref < b.pref);
670 function resolver:peek (qname, qtype, qclass) -- - - - - - - - - - - - peek
671 qname, qtype, qclass = standardize(qname, qtype, qclass);
672 local rrs = get(self.cache, qclass, qtype, qname);
673 if not rrs then return nil; end
674 if prune(rrs, socket.gettime()) and qtype == '*' or not next(rrs) then
675 set(self.cache, qclass, qtype, qname, nil);
678 if self.unsorted[rrs] then table.sort (rrs, comp_mx); end
683 function resolver:purge(soft) -- - - - - - - - - - - - - - - - - - - purge
684 if soft == 'soft' then
685 self.time = socket.gettime();
686 for class,types in pairs(self.cache or {}) do
687 for type,names in pairs(types) do
688 for name,rrs in pairs(names) do
689 prune(rrs, self.time, 'soft')
693 else self.cache = {}; end
697 function resolver:query(qname, qtype, qclass) -- - - - - - - - - - -- query
698 qname, qtype, qclass = standardize(qname, qtype, qclass)
700 if not self.server then self:adddefaultnameservers(); end
702 local question = encodeQuestion(qname, qtype, qclass);
703 local peek = self:peek (qname, qtype, qclass);
704 if peek then return peek; end
706 local header, id = encodeHeader();
707 --print ('query id', id, qclass, qtype, qname)
709 packet = header..question,
710 server = self.best_server,
712 retry = socket.gettime() + self.delays[1]
715 -- remember the query
716 self.active[id] = self.active[id] or {};
717 self.active[id][question] = o;
719 -- remember which coroutine wants the answer
720 local co = coroutine.running();
722 set(self.wanted, qclass, qtype, qname, co, true);
723 --set(self.yielded, co, qclass, qtype, qname, true);
726 local conn = self:getsocket(o.server)
729 if timer and self.timeout then
730 local num_servers = #self.server;
732 timer.add_task(self.timeout, function ()
733 if get(self.wanted, qclass, qtype, qname, co) then
734 if i < num_servers then
737 o.server = self.best_server;
738 conn = self:getsocket(o.server);
742 -- Tried everything, failed
743 self:cancel(qclass, qtype, qname, co, true);
750 function resolver:servfail(sock)
751 -- Resend all queries for this server
753 local num = self.socketset[sock]
755 -- Socket is dead now
756 self:voidsocket(sock);
758 -- Find all requests to the down server, and retry on the next server
759 self.time = socket.gettime();
760 for id,queries in pairs(self.active) do
761 for question,o in pairs(queries) do
762 if o.server == num then -- This request was to the broken server
763 o.server = o.server + 1 -- Use next server
764 if o.server > #self.server then
768 o.retries = (o.retries or 0) + 1;
769 if o.retries >= #self.server then
771 queries[question] = nil;
773 local _a = self:getsocket(o.server);
774 if _a then _a:send(o.packet); end
780 if num == self.best_server then
781 self.best_server = self.best_server + 1;
782 if self.best_server > #self.server then
783 -- Exhausted all servers, try first again
784 self.best_server = 1;
789 function resolver:settimeout(seconds)
790 self.timeout = seconds;
793 function resolver:receive(rset) -- - - - - - - - - - - - - - - - - receive
794 --print('receive'); print(self.socket);
795 self.time = socket.gettime();
796 rset = rset or self.socket;
799 for i,sock in pairs(rset) do
801 if self.socketset[sock] then
802 local packet = sock:receive();
804 response = self:decode(packet);
805 if response and self.active[response.header.id]
806 and self.active[response.header.id][response.question.raw] then
807 --print('received response');
808 --self.print(response);
810 for j,rr in pairs(response.answer) do
811 if rr.name:sub(-#response.question[1].name, -1) == response.question[1].name then
812 self:remember(rr, response.question[1].type)
817 local queries = self.active[response.header.id];
818 queries[response.question.raw] = nil;
820 if not next(queries) then self.active[response.header.id] = nil; end
821 if not next(self.active) then self:closeall(); end
823 -- was the query on the wanted list?
824 local q = response.question[1];
825 local cos = get(self.wanted, q.class, q.type, q.name);
827 for co in pairs(cos) do
828 set(self.yielded, co, q.class, q.type, q.name, nil);
829 if coroutine.status(co) == "suspended" then coroutine.resume(co); end
831 set(self.wanted, q.class, q.type, q.name, nil);
842 function resolver:feed(sock, packet, force)
843 --print('receive'); print(self.socket);
844 self.time = socket.gettime();
846 local response = self:decode(packet, force);
847 if response and self.active[response.header.id]
848 and self.active[response.header.id][response.question.raw] then
849 --print('received response');
850 --self.print(response);
852 for j,rr in pairs(response.answer) do
853 self:remember(rr, response.question[1].type);
857 local queries = self.active[response.header.id];
858 queries[response.question.raw] = nil;
859 if not next(queries) then self.active[response.header.id] = nil; end
860 if not next(self.active) then self:closeall(); end
862 -- was the query on the wanted list?
863 local q = response.question[1];
865 local cos = get(self.wanted, q.class, q.type, q.name);
867 for co in pairs(cos) do
868 set(self.yielded, co, q.class, q.type, q.name, nil);
869 if coroutine.status(co) == "suspended" then coroutine.resume(co); end
871 set(self.wanted, q.class, q.type, q.name, nil);
879 function resolver:cancel(qclass, qtype, qname, co, call_handler)
880 local cos = get(self.wanted, qclass, qtype, qname);
883 coroutine.resume(co);
889 function resolver:pulse() -- - - - - - - - - - - - - - - - - - - - - pulse
891 while self:receive() do end
892 if not next(self.active) then return nil; end
894 self.time = socket.gettime();
895 for id,queries in pairs(self.active) do
896 for question,o in pairs(queries) do
897 if self.time >= o.retry then
899 o.server = o.server + 1;
900 if o.server > #self.server then
902 o.delay = o.delay + 1;
905 if o.delay > #self.delays then
907 queries[question] = nil;
908 if not next(queries) then self.active[id] = nil; end
909 if not next(self.active) then return nil; end
911 --print('retry', o.server, o.delay);
912 local _a = self.socket[o.server];
913 if _a then _a:send(o.packet); end
914 o.retry = self.time + self.delays[o.delay];
920 if next(self.active) then return true; end
925 function resolver:lookup(qname, qtype, qclass) -- - - - - - - - - - lookup
926 self:query (qname, qtype, qclass)
927 while self:pulse() do
929 for i, s in ipairs(self.socket) do
932 socket.select(recvt, nil, 4)
935 return self:peek(qname, qtype, qclass);
938 function resolver:lookupex(handler, qname, qtype, qclass) -- - - - - - - - - - lookup
939 return self:peek(qname, qtype, qclass) or self:query(qname, qtype, qclass);
942 function resolver:tohostname(ip)
943 return dns.lookup(ip:gsub("(%d+)%.(%d+)%.(%d+)%.(%d+)", "%4.%3.%2.%1.in-addr.arpa."), "PTR");
946 --print ---------------------------------------------------------------- print
949 local hints = { -- - - - - - - - - - - - - - - - - - - - - - - - - - - hints
950 qr = { [0]='query', 'response' },
951 opcode = { [0]='query', 'inverse query', 'server status request' },
952 aa = { [0]='non-authoritative', 'authoritative' },
953 tc = { [0]='complete', 'truncated' },
954 rd = { [0]='recursion not desired', 'recursion desired' },
955 ra = { [0]='recursion not available', 'recursion available' },
956 z = { [0]='(reserved)' },
957 rcode = { [0]='no error', 'format error', 'server failure', 'name error', 'not implemented' },
964 local function hint(p, s) -- - - - - - - - - - - - - - - - - - - - - - hint
965 return (hints[s] and hints[s][p[s]]) or '';
969 function resolver.print(response) -- - - - - - - - - - - - - resolver.print
970 for s,s in pairs { 'id', 'qr', 'opcode', 'aa', 'tc', 'rd', 'ra', 'z',
971 'rcode', 'qdcount', 'ancount', 'nscount', 'arcount' } do
972 print( string.format('%-30s', 'header.'..s), response.header[s], hint(response.header, s) );
975 for i,question in ipairs(response.question) do
976 print(string.format ('question[%i].name ', i), question.name);
977 print(string.format ('question[%i].type ', i), question.type);
978 print(string.format ('question[%i].class ', i), question.class);
981 local common = { name=1, type=1, class=1, ttl=1, rdlength=1, rdata=1 };
983 for s,s in pairs({'answer', 'authority', 'additional'}) do
984 for i,rr in pairs(response[s]) do
985 for j,t in pairs({ 'name', 'type', 'class', 'ttl', 'rdlength' }) do
986 tmp = string.format('%s[%i].%s', s, i, t);
987 print(string.format('%-30s', tmp), rr[t], hint(rr, t));
989 for j,t in pairs(rr) do
990 if not common[j] then
991 tmp = string.format('%s[%i].%s', s, i, j);
992 print(string.format('%-30s %s', tostring(tmp), tostring(t)));
1000 -- module api ------------------------------------------------------ module api
1003 function dns.resolver () -- - - - - - - - - - - - - - - - - - - - - resolver
1004 -- this function seems to be redundant with resolver.new ()
1006 local r = { active = {}, cache = {}, unsorted = {}, wanted = {}, yielded = {}, best_server = 1 };
1007 setmetatable (r, resolver);
1008 setmetatable (r.cache, cache_metatable);
1009 setmetatable (r.unsorted, { __mode = 'kv' });
1013 local _resolver = dns.resolver();
1014 dns._resolver = _resolver;
1016 function dns.lookup(...) -- - - - - - - - - - - - - - - - - - - - - lookup
1017 return _resolver:lookup(...);
1020 function dns.tohostname(...)
1021 return _resolver:tohostname(...);
1024 function dns.purge(...) -- - - - - - - - - - - - - - - - - - - - - - purge
1025 return _resolver:purge(...);
1028 function dns.peek(...) -- - - - - - - - - - - - - - - - - - - - - - - peek
1029 return _resolver:peek(...);
1032 function dns.query(...) -- - - - - - - - - - - - - - - - - - - - - - query
1033 return _resolver:query(...);
1036 function dns.feed(...) -- - - - - - - - - - - - - - - - - - - - - - - feed
1037 return _resolver:feed(...);
1040 function dns.cancel(...) -- - - - - - - - - - - - - - - - - - - - - - cancel
1041 return _resolver:cancel(...);
1044 function dns.settimeout(...)
1045 return _resolver:settimeout(...);
1048 function dns.socket_wrapper_set(...) -- - - - - - - - - socket_wrapper_set
1049 return _resolver:socket_wrapper_set(...);