mDNSGw Sources / file comparison
comparison: src/app.js
src/app.js
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| 1 #! /usr/bin/env nodejs | |
| 2 // | |
| 3 // mDNSGw - Zero Configuration DNS Gateway for Mesh Networks | |
| 4 // Copyright © 2014 Michael Schloh von Bennewitz <michael@schloh.com> | |
| 5 // | |
| 6 // Permission to use, copy, modify, and/or distribute this software for | |
| 7 // any purpose with or without fee is hereby granted, provided that the | |
| 8 // above copyright notice and this permission notice appear in all copies. | |
| 9 // | |
| 10 // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL | |
| 11 // WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED | |
| 12 // WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE | |
| 13 // AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL | |
| 14 // DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR | |
| 15 // PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS | |
| 16 // ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF | |
| 17 // THIS SOFTWARE. | |
| 18 // | |
| 19 // This file is part of mDNSGw, a Zero configuration DNS gateway | |
| 20 // which can be found at http://dev.europalab.com/mdnsgw/ | |
| 21 // | |
| 22 // app.js: ECMA JavaScript implementation | |
| 23 // | |
| 24 | |
| 25 /*********************************************************** | |
| 26 | ____ _ _ ____ ____ | | |
| 27 | _ __ ___ | _ \| \ | / ___| / ___|_ __ | | |
| 28 | | '_ ` _ \| | | | \| \___ \| | _\ \ /\ / / | | |
| 29 | | | | | | | |_| | |\ |___) | |_| |\ V V / | | |
| 30 | |_| |_| |_|____/|_| \_|____/ \____| \_/\_/ | | |
| 31 | | | |
| 32 | Requirements: Redis server with standard configuration | | |
| 33 | NodeJS and NPM modules (see package.json) | | |
| 34 | | | |
| 35 | Execute: To start this application, launch it with the | | |
| 36 | script named fork.js: $ ./fork.js | | |
| 37 | | | |
| 38 | Support: http://list.europalab.com/mailman/mdnsgs/ | | |
| 39 | | | |
| 40 ***********************************************************/ | |
| 41 | |
| 42 // import module dependencies | |
| 43 var mdnsinst = require('mdns'); | |
| 44 var redisdat = require('redis'); | |
| 45 var nameinst = require('native-dns'); | |
| 46 | |
| 47 | |
| 48 // instantiate a new redis client | |
| 49 // http://www.rediscookbook.org/ | |
| 50 var rediscli = redisdat.createClient(); | |
| 51 rediscli.on('error', function (error) { | |
| 52 console.log('Error ' + error); | |
| 53 }); | |
| 54 | |
| 55 // clear mDNS service keys | |
| 56 rediscli.del('hostnames'); | |
| 57 // this is not working unfortunately for the loop | |
| 58 rediscli.keys('*', function (error, replies) { | |
| 59 replies.forEach(function (reply, ident) { | |
| 60 rediscli.del(reply, function (error, value) { | |
| 61 if (error) throw(error); | |
| 62 }); | |
| 63 }); | |
| 64 }); | |
| 65 | |
| 66 // scan all advertised mDNS service types | |
| 67 var browsall = mdnsinst.browseThemAll(); | |
| 68 browsall.on('serviceUp', function(service) { | |
| 69 // iterate through hosts and watch accordingly | |
| 70 if (service.type.name.match(/^[a-zA-Z0-9\-]+$/)) { // mdns module hack | |
| 71 if (service.type.protocol == 'tcp') { | |
| 72 var browserv = mdnsinst.createBrowser(mdnsinst.tcp(service.type.name)); | |
| 73 } | |
| 74 else if (service.type.protocol == 'udp') { | |
| 75 var browserv = mdnsinst.createBrowser(mdnsinst.udp(service.type.name)); | |
| 76 } | |
| 77 else if (service.type.protocol == 'sctp') { | |
| 78 var browserv = mdnsinst.createBrowser(mdnsinst.sctp(service.type.name)); | |
| 79 } | |
| 80 else throw(error); | |
| 81 | |
| 82 // common logic for all transports (TCP, UDP, SCTP, etcetera) | |
| 83 browserv.on('serviceUp', function(service) { | |
| 84 //console.log('service up: ', service); | |
| 85 //{interfaceIndex: 2, type: {name: 'ssh', protocol: 'tcp', subtypes: [], fullyQualified: true}, replyDomain: 'local.', flags: 2, name: 'hostname-mich', networkInterface: 'eth0', fullname: 'hostname-mich._ssh._tcp.local.', host: 'hostname-mich.local.', port: 22, addresses: ['192.168.1.50']} | |
| 86 | |
| 87 // insert one or more IP addresses for each hostname.local. | |
| 88 rediscli.hset('hostnames', service.host.replace(/\.$/, ''), service.addresses); | |
| 89 }); | |
| 90 browserv.on('serviceDown', function(service) { | |
| 91 //console.log('service down: ', service); | |
| 92 //FIXME: still need to selectively remove hosts | |
| 93 }); | |
| 94 browserv.start(); | |
| 95 } | |
| 96 }); | |
| 97 browsall.start(); | |
| 98 | |
| 99 // instantiate a new DNS server | |
| 100 var nameserv = nameinst.createServer(); | |
| 101 | |
| 102 nameserv.on('request', function (request, response) { | |
| 103 //console.log(request) | |
| 104 | |
| 105 // ensure that requested hostname is present | |
| 106 rediscli.hget('hostnames', request.question[0].name, function (error, value) { | |
| 107 // handle unexpected errors | |
| 108 if (error) throw(error); | |
| 109 | |
| 110 if (value) { // the db succeeded in finding a match | |
| 111 // populate the DNS response with the chosen hostname | |
| 112 rediscli.hkeys('hostnames', function (error, replies) { | |
| 113 replies.forEach(function (host, index) { | |
| 114 if (request.question[0].name == host) { | |
| 115 rediscli.hget('hostnames', host, function (error, value) { | |
| 116 // handle unexpected errors | |
| 117 if (error) throw(error); | |
| 118 | |
| 119 // FIXME: still must handle multihomed hosts | |
| 120 //// a host might have more than one address | |
| 121 //value.forEach(function (addr, iter) | |
| 122 // set the nameserver address | |
| 123 response.answer.push(nameinst.A({ | |
| 124 name: host, | |
| 125 address: value, | |
| 126 ttl: 600, | |
| 127 })); | |
| 128 response.send(); | |
| 129 }); | |
| 130 } | |
| 131 }); | |
| 132 }); | |
| 133 } | |
| 134 else { | |
| 135 response.answer.push(nameinst.A({ | |
| 136 name: request.question[0].name, | |
| 137 address: '127.0.0.1', | |
| 138 ttl: 600, | |
| 139 })); | |
| 140 response.send(); | |
| 141 } | |
| 142 }); | |
| 143 }); | |
| 144 | |
| 145 // DNS error handler logic | |
| 146 nameserv.on('error', function (err, buff, req, res) { | |
| 147 console.log('DNS problem: ', err.stack); | |
| 148 }); | |
| 149 | |
| 150 nameserv.serve(15353); | |
| 151 | |
| 152 //// debug print all key and value database entries | |
| 153 //rediscli.hgetall('hostnames', function (error, object) {console.dir(object);}); | |
| 154 | |
| 155 //// display stored mDNS service data entries | |
| 156 //rediscli.hkeys('hostnames', function (error, replies) { | |
| 157 // console.log(replies.length + ' replies:'); | |
| 158 // replies.forEach(function (reply, ident) { | |
| 159 // console.log(' ' + ident + ': ' + reply); | |
| 160 // }); | |
| 161 //}); | |
| 162 | |
| 163 //// block executes on program termination | |
| 164 //rediscli.quit(); // cleanup db connection | |
| 165 //browserv.stop(); // zombie scope too bad | |
| 166 //browsall.stop(); |
