Mercurial > lxmppd-hg-xmllex / file comparison
comparison: net/dns.lua
net/dns.lua
- changeset 403
- da92afa267cf
- parent 399
- 93b6587d9afb
- child 453
- a1efb2cb4f9c
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| 402:50f1c09541cd | 403:da92afa267cf |
|---|---|
| 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 | |
| 22 local ipairs, next, pairs, print, setmetatable, tostring, assert, error = | |
| 23 ipairs, next, pairs, print, setmetatable, tostring, assert, error | |
| 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) | |
| 133 local t = {} | |
| 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 | |
| 504 local resolv_conf = io.open("/etc/resolv.conf"); | |
| 505 if resolv_conf then | |
| 506 for line in resolv_conf:lines() do | |
| 507 local address = string.match (line, 'nameserver%s+(%d+%.%d+%.%d+%.%d+)') | |
| 508 if address then self:addnameserver (address) end | |
| 509 end | |
| 510 else -- FIXME correct for windows, using opendns nameservers for now | |
| 511 self:addnameserver ("208.67.222.222") | |
| 512 self:addnameserver ("208.67.220.220") | |
| 513 end | |
| 514 end | |
| 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 | |
| 590 prune (rrs, self.time, 'soft') | |
| 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 | |
| 602 local question = encodeQuestion (qname, qtype, qclass) | |
| 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) | |
| 694 self.socket[o.server]:send (o.packet) | |
| 695 o.retry = self.time + self.delays[o.delay] | |
| 696 end end end end | |
| 697 | |
| 698 if next (self.active) then return true end | |
| 699 return nil | |
| 700 end | |
| 701 | |
| 702 | |
| 703 function resolver:lookup (qname, qtype, qclass) -- - - - - - - - - - lookup | |
| 704 self:query (qname, qtype, qclass) | |
| 705 while self:pulse () do socket.select (self.socket, nil, 4) end | |
| 706 -- print (self.cache) | |
| 707 return self:peek (qname, qtype, qclass) | |
| 708 end | |
| 709 | |
| 710 | |
| 711 -- print ---------------------------------------------------------------- print | |
| 712 | |
| 713 | |
| 714 local hints = { -- - - - - - - - - - - - - - - - - - - - - - - - - - - hints | |
| 715 qr = { [0]='query', 'response' }, | |
| 716 opcode = { [0]='query', 'inverse query', 'server status request' }, | |
| 717 aa = { [0]='non-authoritative', 'authoritative' }, | |
| 718 tc = { [0]='complete', 'truncated' }, | |
| 719 rd = { [0]='recursion not desired', 'recursion desired' }, | |
| 720 ra = { [0]='recursion not available', 'recursion available' }, | |
| 721 z = { [0]='(reserved)' }, | |
| 722 rcode = { [0]='no error', 'format error', 'server failure', 'name error', | |
| 723 'not implemented' }, | |
| 724 | |
| 725 type = dns.type, | |
| 726 class = dns.class, } | |
| 727 | |
| 728 | |
| 729 local function hint (p, s) -- - - - - - - - - - - - - - - - - - - - - - hint | |
| 730 return (hints[s] and hints[s][p[s]]) or '' end | |
| 731 | |
| 732 | |
| 733 function resolver.print (response) -- - - - - - - - - - - - - resolver.print | |
| 734 | |
| 735 for s,s in pairs { 'id', 'qr', 'opcode', 'aa', 'tc', 'rd', 'ra', 'z', | |
| 736 'rcode', 'qdcount', 'ancount', 'nscount', 'arcount' } do | |
| 737 print ( string.format ('%-30s', 'header.'..s), | |
| 738 response.header[s], hint (response.header, s) ) | |
| 739 end | |
| 740 | |
| 741 for i,question in ipairs (response.question) do | |
| 742 print (string.format ('question[%i].name ', i), question.name) | |
| 743 print (string.format ('question[%i].type ', i), question.type) | |
| 744 print (string.format ('question[%i].class ', i), question.class) | |
| 745 end | |
| 746 | |
| 747 local common = { name=1, type=1, class=1, ttl=1, rdlength=1, rdata=1 } | |
| 748 local tmp | |
| 749 for s,s in pairs {'answer', 'authority', 'additional'} do | |
| 750 for i,rr in pairs (response[s]) do | |
| 751 for j,t in pairs { 'name', 'type', 'class', 'ttl', 'rdlength' } do | |
| 752 tmp = string.format ('%s[%i].%s', s, i, t) | |
| 753 print (string.format ('%-30s', tmp), rr[t], hint (rr, t)) | |
| 754 end | |
| 755 for j,t in pairs (rr) do | |
| 756 if not common[j] then | |
| 757 tmp = string.format ('%s[%i].%s', s, i, j) | |
| 758 print (string.format ('%-30s %s', tmp, t)) | |
| 759 end end end end end | |
| 760 | |
| 761 | |
| 762 -- module api ------------------------------------------------------ module api | |
| 763 | |
| 764 | |
| 765 local function resolve (func, ...) -- - - - - - - - - - - - - - resolver_get | |
| 766 dns._resolver = dns._resolver or dns.resolver () | |
| 767 return func (dns._resolver, ...) | |
| 768 end | |
| 769 | |
| 770 | |
| 771 function dns.resolver () -- - - - - - - - - - - - - - - - - - - - - resolver | |
| 772 | |
| 773 -- this function seems to be redundant with resolver.new () | |
| 774 | |
| 775 local r = { active = {}, cache = {}, unsorted = {}, wanted = {}, yielded = {} } | |
| 776 setmetatable (r, resolver) | |
| 777 setmetatable (r.cache, cache_metatable) | |
| 778 setmetatable (r.unsorted, { __mode = 'kv' }) | |
| 779 return r | |
| 780 end | |
| 781 | |
| 782 | |
| 783 function dns.lookup (...) -- - - - - - - - - - - - - - - - - - - - - lookup | |
| 784 return resolve (resolver.lookup, ...) end | |
| 785 | |
| 786 | |
| 787 function dns.purge (...) -- - - - - - - - - - - - - - - - - - - - - - purge | |
| 788 return resolve (resolver.purge, ...) end | |
| 789 | |
| 790 function dns.peek (...) -- - - - - - - - - - - - - - - - - - - - - - - peek | |
| 791 return resolve (resolver.peek, ...) end | |
| 792 | |
| 793 | |
| 794 function dns.query (...) -- - - - - - - - - - - - - - - - - - - - - - query | |
| 795 return resolve (resolver.query, ...) end | |
| 796 | |
| 797 | |
| 798 function dns:socket_wrapper_set (...) -- - - - - - - - - socket_wrapper_set | |
| 799 return resolve (resolver.socket_wrapper_set, ...) end | |
| 800 | |
| 801 | |
| 802 return dns |
