// Copyright Joyent, Inc. and other Node contributors. // // Permission is hereby granted, free of charge, to any person obtaining a // copy of this software and associated documentation files (the // 'Software'), to deal in the Software without restriction, including // without limitation the rights to use, copy, modify, merge, publish, // distribute, sublicense, and/or sell copies of the Software, and to permit // persons to whom the Software is furnished to do so, subject to the // following conditions: // // The above copyright notice and this permission notice shall be included // in all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN // NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE // USE OR OTHER DEALINGS IN THE SOFTWARE. var cares = process.binding('cares_wrap'), net = require('net'), isIp = net.isIP; function errnoException(errorno, syscall) { // TODO make this more compatible with ErrnoException from src/node.cc // Once all of Node is using this function the ErrnoException from // src/node.cc should be removed. var e = new Error(syscall + ' ' + errorno); e.errno = e.code = errorno; e.syscall = syscall; return e; } function familyToSym(family) { switch (family) { case 4: return cares.AF_INET; case 6: return cares.AF_INET6; default: return cares.AF_UNSPEC; } } function symToFamily(family) { switch (family) { case cares.AF_INET: return 4; case cares.AF_INET6: return 6; default: return undefined; } } // c-ares invokes a callback either synchronously or asynchronously, // but the dns API should always invoke a callback asynchronously. // // This function makes sure that the callback is invoked asynchronously. // It returns a function that invokes the callback within nextTick(). // // To avoid invoking unnecessary nextTick(), `immediately` property of // returned function should be set to true after c-ares returned. // // Usage: // // function someAPI(callback) { // callback = makeAsync(callback); // channel.someAPI(..., callback); // callback.immediately = true; // } function makeAsync(callback) { if (typeof callback !== 'function') { return callback; } return function asyncCallback() { if (asyncCallback.immediately) { // The API already returned, we can invoke the callback immediately. callback.apply(null, arguments); } else { var args = arguments; process.nextTick(function() { callback.apply(null, args); }); } }; } // Easy DNS A/AAAA look up // lookup(domain, [family,] callback) exports.lookup = function(domain, family, callback) { // parse arguments if (arguments.length === 2) { callback = family; family = 0; } else if (!family) { family = 0; } else { family = +family; if (family !== 4 && family !== 6) { throw new Error('invalid argument: `family` must be 4 or 6'); } } callback = makeAsync(callback); if (!domain) { callback(null, null, family === 6 ? 6 : 4); return {}; } // Hack required for Windows because Win7 removed the // localhost entry from c:\WINDOWS\system32\drivers\etc\hosts // See http://daniel.haxx.se/blog/2011/02/21/localhost-hack-on-windows/ // TODO Remove this once c-ares handles this problem. if (process.platform == 'win32' && domain == 'localhost') { callback(null, '127.0.0.1', 4); return {}; } var matchedFamily = net.isIP(domain); if (matchedFamily) { callback(null, domain, matchedFamily); return {}; } /* TODO if (/\w\.local\.?$/.test(domain)) { // ANNOYING: In the case of mDNS domains use NSS in the thread pool. // I wish c-ares had better support. process.binding('net').getaddrinfo(domain, 4, function(err, domains4) { callback(err, domains4[0], 4); }); callback.immediately = true; return {}; } */ function onanswer(status, addresses, familySym) { if (!status) { callback(null, addresses[0], symToFamily(familySym)); } else { callback(errnoException(errno, 'getHostByName')); } } var wrap; if (family) { // resolve names for explicit address family var af = familyToSym(family); wrap = cares.getHostByName(domain, af, onanswer); } else { // first resolve names for v4 and if that fails, try v6 wrap = cares.getHostByName(domain, cares.AF_INET, function(err, domains4) { if (domains4 && domains4.length) { callback(null, domains4[0], 4); } else { cares.getHostByName(domain, cares.AF_INET6, onanswer); } }); } if (!wrap) { throw errnoException(errno, 'getHostByName'); } callback.immediately = true; return wrap; }; function resolver(bindingName) { var binding = cares[bindingName]; return function query(name, callback) { function onanswer(status, result) { if (!status) { callback(null, result); } else { callback(errnoException(errno, bindingName)); } } callback = makeAsync(callback); var wrap = binding(name, onanswer); if (!wrap) { throw errnoException(errno, bindingName); } callback.immediately = true; return wrap; } } var resolveMap = {}; exports.resolve4 = resolveMap.A = resolver('queryA'); exports.resolve6 = resolveMap.AAAA = resolver('queryAaaa'); exports.resolveCname = resolveMap.CNAME = resolver('queryCname'); exports.resolveMx = resolveMap.MX = resolver('queryMx'); exports.resolveNs = resolveMap.NS = resolver('queryNs'); exports.resolveTxt = resolveMap.TXT = resolver('queryTxt'); exports.resolveSrv = resolveMap.SRV = resolver('querySrv'); exports.reverse = resolveMap.PTR = resolver('getHostByAddr'); exports.resolve = function(domain, type_, callback_) { var resolver, callback; if (typeof type_ == 'string') { resolver = resolveMap[type_]; callback = callback_; } else { resolver = exports.resolve4; callback = type_; } if (typeof resolver === 'function') { return resolver(domain, callback); } else { throw new Error('Unknown type "' + type + '"'); } }; // ERROR CODES exports.BADNAME = 'EBADNAME'; exports.BADRESP = 'EBADRESP'; exports.CONNREFUSED = 'ECONNREFUSED'; exports.DESTRUCTION = 'EDESTRUCTION'; exports.REFUSED = 'EREFUSED'; exports.FORMERR = 'EFORMERR'; exports.NODATA = 'ENODATA'; exports.NOMEM = 'ENOMEM'; exports.NOTFOUND = 'ENOTFOUND'; exports.NOTIMP = 'ENOTIMP'; exports.SERVFAIL = 'ESERVFAIL'; exports.TIMEOUT = 'ETIMEOUT';