Sun, 30 Nov 2008 17:18:31 +0100
Automerge with waqas.
337 | 1 | |
2 | ||
3 | -- public domain 20080404 lua@ztact.com | |
4 | ||
5 | ||
6 | -- todo: quick (default) header generation | |
7 | -- todo: nxdomain, error handling | |
8 | -- todo: cache results of encodeName | |
9 | ||
10 | ||
11 | -- reference: http://tools.ietf.org/html/rfc1035 | |
12 | -- reference: http://tools.ietf.org/html/rfc1876 (LOC) | |
13 | ||
14 | ||
15 | require 'socket' | |
16 | local ztact = require 'util.ztact' | |
17 | ||
18 | ||
19 | local coroutine, io, math, socket, string, table = | |
20 | coroutine, io, math, socket, string, table | |
21 | ||
379
c5617678cd7b
Fix various mistakes in dns.lua
Matthew Wild <mwild1@gmail.com>
parents:
378
diff
changeset
|
22 | local ipairs, next, pairs, print, setmetatable, tostring, assert, error = |
c5617678cd7b
Fix various mistakes in dns.lua
Matthew Wild <mwild1@gmail.com>
parents:
378
diff
changeset
|
23 | ipairs, next, pairs, print, setmetatable, tostring, assert, error |
337 | 24 | |
25 | local get, set = ztact.get, ztact.set | |
26 | ||
27 | ||
28 | -------------------------------------------------- module dns | |
29 | module ('dns') | |
30 | local dns = _M; | |
31 | ||
32 | ||
33 | -- dns type & class codes ------------------------------ dns type & class codes | |
34 | ||
35 | ||
36 | local append = table.insert | |
37 | ||
38 | ||
39 | local function highbyte (i) -- - - - - - - - - - - - - - - - - - - highbyte | |
40 | return (i-(i%0x100))/0x100 | |
41 | end | |
42 | ||
43 | ||
44 | local function augment (t) -- - - - - - - - - - - - - - - - - - - - augment | |
45 | local a = {} | |
46 | for i,s in pairs (t) do a[i] = s a[s] = s a[string.lower (s)] = s end | |
47 | return a | |
48 | end | |
49 | ||
50 | ||
51 | local function encode (t) -- - - - - - - - - - - - - - - - - - - - - encode | |
52 | local code = {} | |
53 | for i,s in pairs (t) do | |
54 | local word = string.char (highbyte (i), i %0x100) | |
55 | code[i] = word | |
56 | code[s] = word | |
57 | code[string.lower (s)] = word | |
58 | end | |
59 | return code | |
60 | end | |
61 | ||
62 | ||
63 | dns.types = { | |
64 | 'A', 'NS', 'MD', 'MF', 'CNAME', 'SOA', 'MB', 'MG', 'MR', 'NULL', 'WKS', | |
65 | 'PTR', 'HINFO', 'MINFO', 'MX', 'TXT', | |
66 | [ 28] = 'AAAA', [ 29] = 'LOC', [ 33] = 'SRV', | |
67 | [252] = 'AXFR', [253] = 'MAILB', [254] = 'MAILA', [255] = '*' } | |
68 | ||
69 | ||
70 | dns.classes = { 'IN', 'CS', 'CH', 'HS', [255] = '*' } | |
71 | ||
72 | ||
73 | dns.type = augment (dns.types) | |
74 | dns.class = augment (dns.classes) | |
75 | dns.typecode = encode (dns.types) | |
76 | dns.classcode = encode (dns.classes) | |
77 | ||
78 | ||
79 | ||
80 | local function standardize (qname, qtype, qclass) -- - - - - - - standardize | |
81 | if string.byte (qname, -1) ~= 0x2E then qname = qname..'.' end | |
82 | qname = string.lower (qname) | |
83 | return qname, dns.type[qtype or 'A'], dns.class[qclass or 'IN'] | |
84 | end | |
85 | ||
86 | ||
87 | local function prune (rrs, time, soft) -- - - - - - - - - - - - - - - prune | |
88 | ||
89 | time = time or socket.gettime () | |
90 | for i,rr in pairs (rrs) do | |
91 | ||
92 | if rr.tod then | |
93 | -- rr.tod = rr.tod - 50 -- accelerated decripitude | |
94 | rr.ttl = math.floor (rr.tod - time) | |
95 | if rr.ttl <= 0 then rrs[i] = nil end | |
96 | ||
97 | elseif soft == 'soft' then -- What is this? I forget! | |
98 | assert (rr.ttl == 0) | |
99 | rrs[i] = nil | |
100 | end end end | |
101 | ||
102 | ||
103 | -- metatables & co. ------------------------------------------ metatables & co. | |
104 | ||
105 | ||
106 | local resolver = {} | |
107 | resolver.__index = resolver | |
108 | ||
109 | ||
110 | local SRV_tostring | |
111 | ||
112 | ||
113 | local rr_metatable = {} -- - - - - - - - - - - - - - - - - - - rr_metatable | |
114 | function rr_metatable.__tostring (rr) | |
115 | local s0 = string.format ( | |
116 | '%2s %-5s %6i %-28s', rr.class, rr.type, rr.ttl, rr.name ) | |
117 | local s1 = '' | |
118 | if rr.type == 'A' then s1 = ' '..rr.a | |
119 | elseif rr.type == 'MX' then | |
120 | s1 = string.format (' %2i %s', rr.pref, rr.mx) | |
121 | elseif rr.type == 'CNAME' then s1 = ' '..rr.cname | |
122 | elseif rr.type == 'LOC' then s1 = ' '..resolver.LOC_tostring (rr) | |
123 | elseif rr.type == 'NS' then s1 = ' '..rr.ns | |
124 | elseif rr.type == 'SRV' then s1 = ' '..SRV_tostring (rr) | |
125 | elseif rr.type == 'TXT' then s1 = ' '..rr.txt | |
126 | else s1 = ' <UNKNOWN RDATA TYPE>' end | |
127 | return s0..s1 | |
128 | end | |
129 | ||
130 | ||
131 | local rrs_metatable = {} -- - - - - - - - - - - - - - - - - - rrs_metatable | |
132 | function rrs_metatable.__tostring (rrs) | |
379
c5617678cd7b
Fix various mistakes in dns.lua
Matthew Wild <mwild1@gmail.com>
parents:
378
diff
changeset
|
133 | local t = {} |
337 | 134 | for i,rr in pairs (rrs) do append (t, tostring (rr)..'\n') end |
135 | return table.concat (t) | |
136 | end | |
137 | ||
138 | ||
139 | local cache_metatable = {} -- - - - - - - - - - - - - - - - cache_metatable | |
140 | function cache_metatable.__tostring (cache) | |
141 | local time = socket.gettime () | |
142 | local t = {} | |
143 | for class,types in pairs (cache) do | |
144 | for type,names in pairs (types) do | |
145 | for name,rrs in pairs (names) do | |
146 | prune (rrs, time) | |
147 | append (t, tostring (rrs)) end end end | |
148 | return table.concat (t) | |
149 | end | |
150 | ||
151 | ||
152 | function resolver:new () -- - - - - - - - - - - - - - - - - - - - - resolver | |
153 | local r = { active = {}, cache = {}, unsorted = {} } | |
154 | setmetatable (r, resolver) | |
155 | setmetatable (r.cache, cache_metatable) | |
156 | setmetatable (r.unsorted, { __mode = 'kv' }) | |
157 | return r | |
158 | end | |
159 | ||
160 | ||
161 | -- packet layer -------------------------------------------------- packet layer | |
162 | ||
163 | ||
164 | function dns.random (...) -- - - - - - - - - - - - - - - - - - - dns.random | |
165 | math.randomseed (10000*socket.gettime ()) | |
166 | dns.random = math.random | |
167 | return dns.random (...) | |
168 | end | |
169 | ||
170 | ||
171 | local function encodeHeader (o) -- - - - - - - - - - - - - - - encodeHeader | |
172 | ||
173 | o = o or {} | |
174 | ||
175 | o.id = o.id or -- 16b (random) id | |
176 | dns.random (0, 0xffff) | |
177 | ||
178 | o.rd = o.rd or 1 -- 1b 1 recursion desired | |
179 | o.tc = o.tc or 0 -- 1b 1 truncated response | |
180 | o.aa = o.aa or 0 -- 1b 1 authoritative response | |
181 | o.opcode = o.opcode or 0 -- 4b 0 query | |
182 | -- 1 inverse query | |
183 | -- 2 server status request | |
184 | -- 3-15 reserved | |
185 | o.qr = o.qr or 0 -- 1b 0 query, 1 response | |
186 | ||
187 | o.rcode = o.rcode or 0 -- 4b 0 no error | |
188 | -- 1 format error | |
189 | -- 2 server failure | |
190 | -- 3 name error | |
191 | -- 4 not implemented | |
192 | -- 5 refused | |
193 | -- 6-15 reserved | |
194 | o.z = o.z or 0 -- 3b 0 resvered | |
195 | o.ra = o.ra or 0 -- 1b 1 recursion available | |
196 | ||
197 | o.qdcount = o.qdcount or 1 -- 16b number of question RRs | |
198 | o.ancount = o.ancount or 0 -- 16b number of answers RRs | |
199 | o.nscount = o.nscount or 0 -- 16b number of nameservers RRs | |
200 | o.arcount = o.arcount or 0 -- 16b number of additional RRs | |
201 | ||
202 | -- string.char() rounds, so prevent roundup with -0.4999 | |
203 | local header = string.char ( | |
204 | highbyte (o.id), o.id %0x100, | |
205 | o.rd + 2*o.tc + 4*o.aa + 8*o.opcode + 128*o.qr, | |
206 | o.rcode + 16*o.z + 128*o.ra, | |
207 | highbyte (o.qdcount), o.qdcount %0x100, | |
208 | highbyte (o.ancount), o.ancount %0x100, | |
209 | highbyte (o.nscount), o.nscount %0x100, | |
210 | highbyte (o.arcount), o.arcount %0x100 ) | |
211 | ||
212 | return header, o.id | |
213 | end | |
214 | ||
215 | ||
216 | local function encodeName (name) -- - - - - - - - - - - - - - - - encodeName | |
217 | local t = {} | |
218 | for part in string.gmatch (name, '[^.]+') do | |
219 | append (t, string.char (string.len (part))) | |
220 | append (t, part) | |
221 | end | |
222 | append (t, string.char (0)) | |
223 | return table.concat (t) | |
224 | end | |
225 | ||
226 | ||
227 | local function encodeQuestion (qname, qtype, qclass) -- - - - encodeQuestion | |
228 | qname = encodeName (qname) | |
229 | qtype = dns.typecode[qtype or 'a'] | |
230 | qclass = dns.classcode[qclass or 'in'] | |
231 | return qname..qtype..qclass; | |
232 | end | |
233 | ||
234 | ||
235 | function resolver:byte (len) -- - - - - - - - - - - - - - - - - - - - - byte | |
236 | len = len or 1 | |
237 | local offset = self.offset | |
238 | local last = offset + len - 1 | |
239 | if last > #self.packet then | |
240 | error (string.format ('out of bounds: %i>%i', last, #self.packet)) end | |
241 | self.offset = offset + len | |
242 | return string.byte (self.packet, offset, last) | |
243 | end | |
244 | ||
245 | ||
246 | function resolver:word () -- - - - - - - - - - - - - - - - - - - - - - word | |
247 | local b1, b2 = self:byte (2) | |
248 | return 0x100*b1 + b2 | |
249 | end | |
250 | ||
251 | ||
252 | function resolver:dword () -- - - - - - - - - - - - - - - - - - - - - dword | |
253 | local b1, b2, b3, b4 = self:byte (4) | |
254 | -- print ('dword', b1, b2, b3, b4) | |
255 | return 0x1000000*b1 + 0x10000*b2 + 0x100*b3 + b4 | |
256 | end | |
257 | ||
258 | ||
259 | function resolver:sub (len) -- - - - - - - - - - - - - - - - - - - - - - sub | |
260 | len = len or 1 | |
261 | local s = string.sub (self.packet, self.offset, self.offset + len - 1) | |
262 | self.offset = self.offset + len | |
263 | return s | |
264 | end | |
265 | ||
266 | ||
267 | function resolver:header (force) -- - - - - - - - - - - - - - - - - - header | |
268 | ||
269 | local id = self:word () | |
270 | -- print (string.format (':header id %x', id)) | |
271 | if not self.active[id] and not force then return nil end | |
272 | ||
273 | local h = { id = id } | |
274 | ||
275 | local b1, b2 = self:byte (2) | |
276 | ||
277 | h.rd = b1 %2 | |
278 | h.tc = b1 /2%2 | |
279 | h.aa = b1 /4%2 | |
280 | h.opcode = b1 /8%16 | |
281 | h.qr = b1 /128 | |
282 | ||
283 | h.rcode = b2 %16 | |
284 | h.z = b2 /16%8 | |
285 | h.ra = b2 /128 | |
286 | ||
287 | h.qdcount = self:word () | |
288 | h.ancount = self:word () | |
289 | h.nscount = self:word () | |
290 | h.arcount = self:word () | |
291 | ||
292 | for k,v in pairs (h) do h[k] = v-v%1 end | |
293 | ||
294 | return h | |
295 | end | |
296 | ||
297 | ||
298 | function resolver:name () -- - - - - - - - - - - - - - - - - - - - - - name | |
299 | local remember, pointers = nil, 0 | |
300 | local len = self:byte () | |
301 | local n = {} | |
302 | while len > 0 do | |
303 | if len >= 0xc0 then -- name is "compressed" | |
304 | pointers = pointers + 1 | |
305 | if pointers >= 20 then error ('dns error: 20 pointers') end | |
306 | local offset = ((len-0xc0)*0x100) + self:byte () | |
307 | remember = remember or self.offset | |
308 | self.offset = offset + 1 -- +1 for lua | |
309 | else -- name is not compressed | |
310 | append (n, self:sub (len)..'.') | |
311 | end | |
312 | len = self:byte () | |
313 | end | |
314 | self.offset = remember or self.offset | |
315 | return table.concat (n) | |
316 | end | |
317 | ||
318 | ||
319 | function resolver:question () -- - - - - - - - - - - - - - - - - - question | |
320 | local q = {} | |
321 | q.name = self:name () | |
322 | q.type = dns.type[self:word ()] | |
323 | q.class = dns.type[self:word ()] | |
324 | return q | |
325 | end | |
326 | ||
327 | ||
328 | function resolver:A (rr) -- - - - - - - - - - - - - - - - - - - - - - - - A | |
329 | local b1, b2, b3, b4 = self:byte (4) | |
330 | rr.a = string.format ('%i.%i.%i.%i', b1, b2, b3, b4) | |
331 | end | |
332 | ||
333 | ||
334 | function resolver:CNAME (rr) -- - - - - - - - - - - - - - - - - - - - CNAME | |
335 | rr.cname = self:name () | |
336 | end | |
337 | ||
338 | ||
339 | function resolver:MX (rr) -- - - - - - - - - - - - - - - - - - - - - - - MX | |
340 | rr.pref = self:word () | |
341 | rr.mx = self:name () | |
342 | end | |
343 | ||
344 | ||
345 | function resolver:LOC_nibble_power () -- - - - - - - - - - LOC_nibble_power | |
346 | local b = self:byte () | |
347 | -- print ('nibbles', ((b-(b%0x10))/0x10), (b%0x10)) | |
348 | return ((b-(b%0x10))/0x10) * (10^(b%0x10)) | |
349 | end | |
350 | ||
351 | ||
352 | function resolver:LOC (rr) -- - - - - - - - - - - - - - - - - - - - - - LOC | |
353 | rr.version = self:byte () | |
354 | if rr.version == 0 then | |
355 | rr.loc = rr.loc or {} | |
356 | rr.loc.size = self:LOC_nibble_power () | |
357 | rr.loc.horiz_pre = self:LOC_nibble_power () | |
358 | rr.loc.vert_pre = self:LOC_nibble_power () | |
359 | rr.loc.latitude = self:dword () | |
360 | rr.loc.longitude = self:dword () | |
361 | rr.loc.altitude = self:dword () | |
362 | end end | |
363 | ||
364 | ||
365 | local function LOC_tostring_degrees (f, pos, neg) -- - - - - - - - - - - - - | |
366 | f = f - 0x80000000 | |
367 | if f < 0 then pos = neg f = -f end | |
368 | local deg, min, msec | |
369 | msec = f%60000 | |
370 | f = (f-msec)/60000 | |
371 | min = f%60 | |
372 | deg = (f-min)/60 | |
373 | return string.format ('%3d %2d %2.3f %s', deg, min, msec/1000, pos) | |
374 | end | |
375 | ||
376 | ||
377 | function resolver.LOC_tostring (rr) -- - - - - - - - - - - - - LOC_tostring | |
378 | ||
379 | local t = {} | |
380 | ||
381 | --[[ | |
382 | for k,name in pairs { 'size', 'horiz_pre', 'vert_pre', | |
383 | 'latitude', 'longitude', 'altitude' } do | |
384 | append (t, string.format ('%4s%-10s: %12.0f\n', '', name, rr.loc[name])) | |
385 | end | |
386 | --]] | |
387 | ||
388 | append ( t, string.format ( | |
389 | '%s %s %.2fm %.2fm %.2fm %.2fm', | |
390 | LOC_tostring_degrees (rr.loc.latitude, 'N', 'S'), | |
391 | LOC_tostring_degrees (rr.loc.longitude, 'E', 'W'), | |
392 | (rr.loc.altitude - 10000000) / 100, | |
393 | rr.loc.size / 100, | |
394 | rr.loc.horiz_pre / 100, | |
395 | rr.loc.vert_pre / 100 ) ) | |
396 | ||
397 | return table.concat (t) | |
398 | end | |
399 | ||
400 | ||
401 | function resolver:NS (rr) -- - - - - - - - - - - - - - - - - - - - - - - NS | |
402 | rr.ns = self:name () | |
403 | end | |
404 | ||
405 | ||
406 | function resolver:SOA (rr) -- - - - - - - - - - - - - - - - - - - - - - SOA | |
407 | end | |
408 | ||
409 | ||
410 | function resolver:SRV (rr) -- - - - - - - - - - - - - - - - - - - - - - SRV | |
411 | rr.srv = {} | |
412 | rr.srv.priority = self:word () | |
413 | rr.srv.weight = self:word () | |
414 | rr.srv.port = self:word () | |
415 | rr.srv.target = self:name () | |
416 | end | |
417 | ||
418 | ||
419 | function SRV_tostring (rr) -- - - - - - - - - - - - - - - - - - SRV_tostring | |
420 | local s = rr.srv | |
421 | return string.format ( '%5d %5d %5d %s', | |
422 | s.priority, s.weight, s.port, s.target ) | |
423 | end | |
424 | ||
425 | ||
426 | function resolver:TXT (rr) -- - - - - - - - - - - - - - - - - - - - - - TXT | |
427 | rr.txt = self:sub (rr.rdlength) | |
428 | end | |
429 | ||
430 | ||
431 | function resolver:rr () -- - - - - - - - - - - - - - - - - - - - - - - - rr | |
432 | local rr = {} | |
433 | setmetatable (rr, rr_metatable) | |
434 | rr.name = self:name (self) | |
435 | rr.type = dns.type[self:word ()] or rr.type | |
436 | rr.class = dns.class[self:word ()] or rr.class | |
437 | rr.ttl = 0x10000*self:word () + self:word () | |
438 | rr.rdlength = self:word () | |
439 | ||
440 | if rr.ttl == 0 then -- pass | |
441 | else rr.tod = self.time + rr.ttl end | |
442 | ||
443 | local remember = self.offset | |
444 | local rr_parser = self[dns.type[rr.type]] | |
445 | if rr_parser then rr_parser (self, rr) end | |
446 | self.offset = remember | |
447 | rr.rdata = self:sub (rr.rdlength) | |
448 | return rr | |
449 | end | |
450 | ||
451 | ||
452 | function resolver:rrs (count) -- - - - - - - - - - - - - - - - - - - - - rrs | |
453 | local rrs = {} | |
454 | for i = 1,count do append (rrs, self:rr ()) end | |
455 | return rrs | |
456 | end | |
457 | ||
458 | ||
459 | function resolver:decode (packet, force) -- - - - - - - - - - - - - - decode | |
460 | ||
461 | self.packet, self.offset = packet, 1 | |
462 | local header = self:header (force) | |
463 | if not header then return nil end | |
464 | local response = { header = header } | |
465 | ||
466 | response.question = {} | |
467 | local offset = self.offset | |
468 | for i = 1,response.header.qdcount do | |
469 | append (response.question, self:question ()) end | |
470 | response.question.raw = string.sub (self.packet, offset, self.offset - 1) | |
471 | ||
472 | if not force then | |
473 | if not self.active[response.header.id] or | |
474 | not self.active[response.header.id][response.question.raw] then | |
475 | return nil end end | |
476 | ||
477 | response.answer = self:rrs (response.header.ancount) | |
478 | response.authority = self:rrs (response.header.nscount) | |
479 | response.additional = self:rrs (response.header.arcount) | |
480 | ||
481 | return response | |
482 | end | |
483 | ||
484 | ||
485 | -- socket layer -------------------------------------------------- socket layer | |
486 | ||
487 | ||
488 | resolver.delays = { 1, 3, 11, 45 } | |
489 | ||
490 | ||
491 | function resolver:addnameserver (address) -- - - - - - - - - - addnameserver | |
492 | self.server = self.server or {} | |
493 | append (self.server, address) | |
494 | end | |
495 | ||
496 | ||
497 | function resolver:setnameserver (address) -- - - - - - - - - - setnameserver | |
498 | self.server = {} | |
499 | self:addnameserver (address) | |
500 | end | |
501 | ||
502 | ||
503 | function resolver:adddefaultnameservers () -- - - - - adddefaultnameservers | |
378
47fdbd074641
Fix dns for poor Windows users, who have never seen a resolv.conf
Matthew Wild <mwild1@gmail.com>
parents:
337
diff
changeset
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504 | local resolv_conf = io.open("/etc/resolv.conf"); |
399
93b6587d9afb
Added temporary fix for srv on windows: using opendns nameservers
Waqas Hussain <waqas20@gmail.com>
parents:
379
diff
changeset
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505 | if resolv_conf then |
93b6587d9afb
Added temporary fix for srv on windows: using opendns nameservers
Waqas Hussain <waqas20@gmail.com>
parents:
379
diff
changeset
|
506 | for line in resolv_conf:lines() do |
93b6587d9afb
Added temporary fix for srv on windows: using opendns nameservers
Waqas Hussain <waqas20@gmail.com>
parents:
379
diff
changeset
|
507 | local address = string.match (line, 'nameserver%s+(%d+%.%d+%.%d+%.%d+)') |
93b6587d9afb
Added temporary fix for srv on windows: using opendns nameservers
Waqas Hussain <waqas20@gmail.com>
parents:
379
diff
changeset
|
508 | if address then self:addnameserver (address) end |
93b6587d9afb
Added temporary fix for srv on windows: using opendns nameservers
Waqas Hussain <waqas20@gmail.com>
parents:
379
diff
changeset
|
509 | end |
93b6587d9afb
Added temporary fix for srv on windows: using opendns nameservers
Waqas Hussain <waqas20@gmail.com>
parents:
379
diff
changeset
|
510 | else -- FIXME correct for windows, using opendns nameservers for now |
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511 | self:addnameserver ("208.67.222.222") |
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512 | self:addnameserver ("208.67.220.220") |
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513 | end |
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514 | end |
337 | 515 | |
516 | ||
517 | function resolver:getsocket (servernum) -- - - - - - - - - - - - - getsocket | |
518 | ||
519 | self.socket = self.socket or {} | |
520 | self.socketset = self.socketset or {} | |
521 | ||
522 | local sock = self.socket[servernum] | |
523 | if sock then return sock end | |
524 | ||
525 | sock = socket.udp () | |
526 | if self.socket_wrapper then sock = self.socket_wrapper (sock) end | |
527 | sock:settimeout (0) | |
528 | -- todo: attempt to use a random port, fallback to 0 | |
529 | sock:setsockname ('*', 0) | |
530 | sock:setpeername (self.server[servernum], 53) | |
531 | self.socket[servernum] = sock | |
532 | self.socketset[sock] = sock | |
533 | return sock | |
534 | end | |
535 | ||
536 | ||
537 | function resolver:socket_wrapper_set (func) -- - - - - - - socket_wrapper_set | |
538 | self.socket_wrapper = func | |
539 | end | |
540 | ||
541 | ||
542 | function resolver:closeall () -- - - - - - - - - - - - - - - - - - closeall | |
543 | for i,sock in ipairs (self.socket) do self.socket[i]:close () end | |
544 | self.socket = {} | |
545 | end | |
546 | ||
547 | ||
548 | function resolver:remember (rr, type) -- - - - - - - - - - - - - - remember | |
549 | ||
550 | -- print ('remember', type, rr.class, rr.type, rr.name) | |
551 | ||
552 | if type ~= '*' then | |
553 | type = rr.type | |
554 | local all = get (self.cache, rr.class, '*', rr.name) | |
555 | -- print ('remember all', all) | |
556 | if all then append (all, rr) end | |
557 | end | |
558 | ||
559 | self.cache = self.cache or setmetatable ({}, cache_metatable) | |
560 | local rrs = get (self.cache, rr.class, type, rr.name) or | |
561 | set (self.cache, rr.class, type, rr.name, setmetatable ({}, rrs_metatable)) | |
562 | append (rrs, rr) | |
563 | ||
564 | if type == 'MX' then self.unsorted[rrs] = true end | |
565 | end | |
566 | ||
567 | ||
568 | local function comp_mx (a, b) -- - - - - - - - - - - - - - - - - - - comp_mx | |
569 | return (a.pref == b.pref) and (a.mx < b.mx) or (a.pref < b.pref) | |
570 | end | |
571 | ||
572 | ||
573 | function resolver:peek (qname, qtype, qclass) -- - - - - - - - - - - - peek | |
574 | qname, qtype, qclass = standardize (qname, qtype, qclass) | |
575 | local rrs = get (self.cache, qclass, qtype, qname) | |
576 | if not rrs then return nil end | |
577 | if prune (rrs, socket.gettime ()) and qtype == '*' or not next (rrs) then | |
578 | set (self.cache, qclass, qtype, qname, nil) return nil end | |
579 | if self.unsorted[rrs] then table.sort (rrs, comp_mx) end | |
580 | return rrs | |
581 | end | |
582 | ||
583 | ||
584 | function resolver:purge (soft) -- - - - - - - - - - - - - - - - - - - purge | |
585 | if soft == 'soft' then | |
586 | self.time = socket.gettime () | |
587 | for class,types in pairs (self.cache or {}) do | |
588 | for type,names in pairs (types) do | |
589 | for name,rrs in pairs (names) do | |
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590 | prune (rrs, self.time, 'soft') |
337 | 591 | end end end |
592 | else self.cache = {} end | |
593 | end | |
594 | ||
595 | ||
596 | function resolver:query (qname, qtype, qclass) -- - - - - - - - - - -- query | |
597 | ||
598 | qname, qtype, qclass = standardize (qname, qtype, qclass) | |
599 | ||
600 | if not self.server then self:adddefaultnameservers () end | |
601 | ||
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602 | local question = encodeQuestion (qname, qtype, qclass) |
337 | 603 | local peek = self:peek (qname, qtype, qclass) |
604 | if peek then return peek end | |
605 | ||
606 | local header, id = encodeHeader () | |
607 | -- print ('query id', id, qclass, qtype, qname) | |
608 | local o = { packet = header..question, | |
609 | server = 1, | |
610 | delay = 1, | |
611 | retry = socket.gettime () + self.delays[1] } | |
612 | self:getsocket (o.server):send (o.packet) | |
613 | ||
614 | -- remember the query | |
615 | self.active[id] = self.active[id] or {} | |
616 | self.active[id][question] = o | |
617 | ||
618 | -- remember which coroutine wants the answer | |
619 | local co = coroutine.running () | |
620 | if co then | |
621 | set (self.wanted, qclass, qtype, qname, co, true) | |
622 | set (self.yielded, co, qclass, qtype, qname, true) | |
623 | end end | |
624 | ||
625 | ||
626 | function resolver:receive (rset) -- - - - - - - - - - - - - - - - - receive | |
627 | ||
628 | -- print 'receive' print (self.socket) | |
629 | self.time = socket.gettime () | |
630 | rset = rset or self.socket | |
631 | ||
632 | local response | |
633 | for i,sock in pairs (rset) do | |
634 | ||
635 | if self.socketset[sock] then | |
636 | local packet = sock:receive () | |
637 | if packet then | |
638 | ||
639 | response = self:decode (packet) | |
640 | if response then | |
641 | -- print 'received response' | |
642 | -- self.print (response) | |
643 | ||
644 | for i,section in pairs { 'answer', 'authority', 'additional' } do | |
645 | for j,rr in pairs (response[section]) do | |
646 | self:remember (rr, response.question[1].type) end end | |
647 | ||
648 | -- retire the query | |
649 | local queries = self.active[response.header.id] | |
650 | if queries[response.question.raw] then | |
651 | queries[response.question.raw] = nil end | |
652 | if not next (queries) then self.active[response.header.id] = nil end | |
653 | if not next (self.active) then self:closeall () end | |
654 | ||
655 | -- was the query on the wanted list? | |
656 | local q = response.question | |
657 | local cos = get (self.wanted, q.class, q.type, q.name) | |
658 | if cos then | |
659 | for co in pairs (cos) do | |
660 | set (self.yielded, co, q.class, q.type, q.name, nil) | |
661 | if not self.yielded[co] then coroutine.resume (co) end | |
662 | end | |
663 | set (self.wanted, q.class, q.type, q.name, nil) | |
664 | end end end end end | |
665 | ||
666 | return response | |
667 | end | |
668 | ||
669 | ||
670 | function resolver:pulse () -- - - - - - - - - - - - - - - - - - - - - pulse | |
671 | ||
672 | -- print ':pulse' | |
673 | while self:receive () do end | |
674 | if not next (self.active) then return nil end | |
675 | ||
676 | self.time = socket.gettime () | |
677 | for id,queries in pairs (self.active) do | |
678 | for question,o in pairs (queries) do | |
679 | if self.time >= o.retry then | |
680 | ||
681 | o.server = o.server + 1 | |
682 | if o.server > #self.server then | |
683 | o.server = 1 | |
684 | o.delay = o.delay + 1 | |
685 | end | |
686 | ||
687 | if o.delay > #self.delays then | |
688 | print ('timeout') | |
689 | queries[question] = nil | |
690 | if not next (queries) then self.active[id] = nil end | |
691 | if not next (self.active) then return nil end | |
692 | else | |
693 | -- print ('retry', o.server, o.delay) | |
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694 | local _a = self.socket[o.server]; |
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695 | if _a then _a:send (o.packet) end |
337 | 696 | o.retry = self.time + self.delays[o.delay] |
697 | end end end end | |
698 | ||
699 | if next (self.active) then return true end | |
700 | return nil | |
701 | end | |
702 | ||
703 | ||
704 | function resolver:lookup (qname, qtype, qclass) -- - - - - - - - - - lookup | |
705 | self:query (qname, qtype, qclass) | |
706 | while self:pulse () do socket.select (self.socket, nil, 4) end | |
707 | -- print (self.cache) | |
708 | return self:peek (qname, qtype, qclass) | |
709 | end | |
710 | ||
711 | ||
712 | -- print ---------------------------------------------------------------- print | |
713 | ||
714 | ||
715 | local hints = { -- - - - - - - - - - - - - - - - - - - - - - - - - - - hints | |
716 | qr = { [0]='query', 'response' }, | |
717 | opcode = { [0]='query', 'inverse query', 'server status request' }, | |
718 | aa = { [0]='non-authoritative', 'authoritative' }, | |
719 | tc = { [0]='complete', 'truncated' }, | |
720 | rd = { [0]='recursion not desired', 'recursion desired' }, | |
721 | ra = { [0]='recursion not available', 'recursion available' }, | |
722 | z = { [0]='(reserved)' }, | |
723 | rcode = { [0]='no error', 'format error', 'server failure', 'name error', | |
724 | 'not implemented' }, | |
725 | ||
726 | type = dns.type, | |
727 | class = dns.class, } | |
728 | ||
729 | ||
730 | local function hint (p, s) -- - - - - - - - - - - - - - - - - - - - - - hint | |
731 | return (hints[s] and hints[s][p[s]]) or '' end | |
732 | ||
733 | ||
734 | function resolver.print (response) -- - - - - - - - - - - - - resolver.print | |
735 | ||
736 | for s,s in pairs { 'id', 'qr', 'opcode', 'aa', 'tc', 'rd', 'ra', 'z', | |
737 | 'rcode', 'qdcount', 'ancount', 'nscount', 'arcount' } do | |
738 | print ( string.format ('%-30s', 'header.'..s), | |
739 | response.header[s], hint (response.header, s) ) | |
740 | end | |
741 | ||
742 | for i,question in ipairs (response.question) do | |
743 | print (string.format ('question[%i].name ', i), question.name) | |
744 | print (string.format ('question[%i].type ', i), question.type) | |
745 | print (string.format ('question[%i].class ', i), question.class) | |
746 | end | |
747 | ||
748 | local common = { name=1, type=1, class=1, ttl=1, rdlength=1, rdata=1 } | |
749 | local tmp | |
750 | for s,s in pairs {'answer', 'authority', 'additional'} do | |
751 | for i,rr in pairs (response[s]) do | |
752 | for j,t in pairs { 'name', 'type', 'class', 'ttl', 'rdlength' } do | |
753 | tmp = string.format ('%s[%i].%s', s, i, t) | |
754 | print (string.format ('%-30s', tmp), rr[t], hint (rr, t)) | |
755 | end | |
756 | for j,t in pairs (rr) do | |
757 | if not common[j] then | |
758 | tmp = string.format ('%s[%i].%s', s, i, j) | |
759 | print (string.format ('%-30s %s', tmp, t)) | |
760 | end end end end end | |
761 | ||
762 | ||
763 | -- module api ------------------------------------------------------ module api | |
764 | ||
765 | ||
766 | local function resolve (func, ...) -- - - - - - - - - - - - - - resolver_get | |
767 | dns._resolver = dns._resolver or dns.resolver () | |
768 | return func (dns._resolver, ...) | |
769 | end | |
770 | ||
771 | ||
772 | function dns.resolver () -- - - - - - - - - - - - - - - - - - - - - resolver | |
773 | ||
774 | -- this function seems to be redundant with resolver.new () | |
775 | ||
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776 | local r = { active = {}, cache = {}, unsorted = {}, wanted = {}, yielded = {} } |
337 | 777 | setmetatable (r, resolver) |
778 | setmetatable (r.cache, cache_metatable) | |
779 | setmetatable (r.unsorted, { __mode = 'kv' }) | |
780 | return r | |
781 | end | |
782 | ||
783 | ||
784 | function dns.lookup (...) -- - - - - - - - - - - - - - - - - - - - - lookup | |
785 | return resolve (resolver.lookup, ...) end | |
786 | ||
787 | ||
788 | function dns.purge (...) -- - - - - - - - - - - - - - - - - - - - - - purge | |
789 | return resolve (resolver.purge, ...) end | |
790 | ||
791 | function dns.peek (...) -- - - - - - - - - - - - - - - - - - - - - - - peek | |
792 | return resolve (resolver.peek, ...) end | |
793 | ||
794 | ||
795 | function dns.query (...) -- - - - - - - - - - - - - - - - - - - - - - query | |
796 | return resolve (resolver.query, ...) end | |
797 | ||
798 | ||
799 | function dns:socket_wrapper_set (...) -- - - - - - - - - socket_wrapper_set | |
800 | return resolve (resolver.socket_wrapper_set, ...) end | |
801 | ||
802 | ||
803 | return dns |