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digd.js
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WIP dns store

This commit is contained in:
AJ ONeal 2017-10-06 15:34:36 -06:00
parent 8131de4a08
commit 4734b5ac57
4 changed files with 372 additions and 5 deletions
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59
HOW_DELEGATION_WORKS.md
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@ -166,3 +166,62 @@ but I but you could do something weird like host `whatever.john.daplie.me` on th
nameserver by A) answering to it directly on the main nameserver and B) delegating nameserver by A) answering to it directly on the main nameserver and B) delegating
from `whatever.john.daplie.me` back to the original nameserver in case the resolving from `whatever.john.daplie.me` back to the original nameserver in case the resolving
client makes intelligent assumptions and caching. client makes intelligent assumptions and caching.
When a domain doesn't exist
---------------------------
### NXDOMAIN
This nameserver can respond for that domain, but no record exists
```
dig @ns1.google.com doesntexist.google.com
```
```
; <<>> DiG 9.8.3-P1 <<>> @ns1.google.com doesntexist.google.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 45549
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;doesntexist.google.com. IN A
;; AUTHORITY SECTION:
google.com. 60 IN SOA ns2.google.com. dns-admin.google.com. 170961396 900 900 1800 60
;; Query time: 50 msec
;; SERVER: 216.239.32.10#53(216.239.32.10)
;; WHEN: Wed Oct 4 01:14:09 2017
;; MSG SIZE rcvd: 90
```
### REFUSED
This nameserver does not store records for that domain
(and would appreciated it if you didn't ask)
```bash
dig @ns1.google.com daplie.com
```
```
; <<>> DiG 9.8.3-P1 <<>> @ns1.google.com daplie.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: REFUSED, id: 47317
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;daplie.com. IN A
;; Query time: 52 msec
;; SERVER: 216.239.32.10#53(216.239.32.10)
;; WHEN: Wed Oct 4 01:14:20 2017
;; MSG SIZE rcvd: 28
```

4
bin/digd.js
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@ -169,6 +169,10 @@ cli.main(function (args, cli) {
} }
function sendEmptyResponse(query, nx) { function sendEmptyResponse(query, nx) {
// rcode
// 0 SUCCESS // manages this domain and found a record
// 3 NXDOMAIN // manages this domain, but doesn't have a record
// 5 REFUSED // doesn't manage this domain
var newAb; var newAb;
var emptyResp = { var emptyResp = {
header: { header: {

253
lib/dns-store.js
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@ -2,16 +2,259 @@
'use strict'; 'use strict';
/* /*
var fs = require('fs');
module.exports.ask = function (query, cb) { module.exports.ask = function (query, cb) {
}; };
*/ */
module.exports.query = function (input, query, cb) { var SUCCESS = 0;
process.nextTick(function () { var NXDOMAIN = 3;
cb(new Error('No local lookup method for DNS records defined.')); var REFUSED = 5;
function getRecords(db, qname) {
var myRecords = db.records.filter(function (r) {
if ('string' !== typeof r.domain) {
return false;
}
// TODO use IN in masterquest (or implement OR)
// Only return single-level wildcard?
if (qname === r.domain || ('*.' + qname.split('.').slice(1).join('.')) === r.domain) {
return true;
}
}); });
return myRecords;
}
function dbToResourceRecord(r) {
return {
name: r.domain
, typeName: r.type // NS
, className: 'IN'
, ttl: r.ttl || 300
// SOA
/*
, "primary": "ns1.yahoo.com"
, "admin": "hostmaster.yahoo-inc.com"
, "serial": 2017092539
, "refresh": 3600
, "retry": 300
, "expiration": 1814400
, "minimum": 600
*/
// A, AAAA
, address: -1 !== [ 'A', 'AAAA' ].indexOf(r.type) ? (r.address || r.value) : undefined
// CNAME, NS, PTR || TXT
, data: -1 !== [ 'CNAME', 'NS', 'PTR', 'TXT' ].indexOf(r.type) ? (r.value || r.values) : undefined
// MX, SRV
, priority: r.priority
// MX
, exchange: r.exchange
// SRV
, weight: r.weight
, port: r.port
, target: r.target
};
}
function getNs(db, ds, results, cb) {
var d = ds.shift();
if (!d) {
results.rcode = NXDOMAIN;
cb(null, results);
return;
}
var qn = d.id.toLowerCase();
getRecords(db, qn).forEach(function (r) {
if ('NS' !== r.type) {
return;
}
results.authority.push({
name: r.domain
, typeName: r.type // NS
, className: 'IN'
, ttl: r.ttl || 300
, data: r.value
});
});
if (results.authority.length) {
cb(null, results);
return;
}
}
function getSoa(db, domain, results, cb) {
var index = Math.floor(Math.random() * domain.nameservers.length) % domain.nameservers.length;
var nameserver = domain.nameservers[index];
results.authority.push({
name: domain.id
, typeName: 'SOA'
, className: 'IN'
, ttl: domain.ttl || 60
// nameserver -- select an NS at random if they're all in sync
, primary: nameserver
, name_server: nameserver
// admin -- email address or domain for admin
, admin: domain.admin
, email_addr: domain.admin
// serial -- the version, for cache-busting of secondary nameservers. suggested format: YYYYMMDDnn
, serial: domain.serial || Math.round((domain.updatedAt || domain.createdAt) / 1000)
, sn: domain.serial || Math.round((domain.updatedAt || domain.createdAt) / 1000)
// refresh -- only used when nameservers following the DNS NOTIFY spec talk
, refresh: domain.refresh || 1800
, ref: domain.refresh || 1800
// retry -- only used when nameservers following the DNS NOTIFY spec talk
, retry: domain.retry || 600
, ret: domain.retry || 600
// expiration -- how long other nameservers should continue when the primary goes down
, expiration: domain.expiration || 2419200
, ex: domain.expiration || 2419200
// minimum -- how long to cache a non-existent domain (also the default ttl for BIND)
, minimum: domain.minimum || 5
, nx: domain.minimum || 5
});
cb(null, results);
return;
}
module.exports.query = function (input, query, cb) {
/*
var fs = require('fs');
fs.readFile(input, 'utf8', function (err, text) {
if (err) { cb(err); return; }
var records;
try {
records = JSON.parse(text);
} catch(e) { cb(e); return; }
});
*/
var db;
var qname;
try {
db = require(input);
} catch(e) { cb(e); return; }
if (!Array.isArray(query.question) || query.question.length < 1) {
cb(new Error("query is missing question section"));
return;
}
if (1 !== query.question.length) {
cb(new Error("query should have exactly one question (for now)"));
return;
}
if (!query.question[0] || 'string' !== typeof query.question[0].name) {
cb(new Error("query's question section should exist and have a String name property"));
return;
}
qname = query.question[0].name.toLowerCase();
var results = {
header: {
id: query.header.id // same as request
, qr: 1
, opcode: 0 // pretty much always 0 QUERY
, aa: 1 // TODO right now we assume that if we have the record, we're authoritative
// but in reality we could be hitting a cache and then recursing on a cache miss
, tc: 0
, rd: query.header.rd // duh
, ra: 0 // will be changed by cli.norecurse
, rcode: SUCCESS // 0 SUCCESS, 3 NXDOMAIN, 5 REFUSED
}
, question: [], answer: [], authority: [], additional: []
};
var myRecords = getRecords(db, qname);
if (myRecords.length) {
myRecords.forEach(function (r) {
results.answer.push(dbToResourceRecord(r));
});
return;
}
if (!myRecords.length) {
// If the query is www.foo.delegated.example.com
// and we have been delegated delegated.example.com
// and delegated.example.com exists
// but foo.delegated.example.com does not exist
// what's the best strategy for returning the record?
//
// What does PowerDNS do in these situations?
// https://doc.powerdns.com/md/authoritative/backend-generic-mysql/
// How to optimize:
// Assume that if a record is being requested, it probably exists
// (someone has probably published it somewhere)
// If the record doesn't exist, then see if any of the domains are managed
// [ 'www.john.smithfam.net', 'john.smithfam.net', 'smithfam.net', 'net' ]
// Then if one of those exists, return the SOA record with NXDOMAIN
var qarr = qname.split('.');
var qnames = [];
while (qarr.length) {
qnames.push(qarr.join('.').toLowerCase());
qarr.shift(); // first
}
var myDomains = db.domains.filter(function (d) {
return -1 !== qnames.indexOf(d.id.toLowerCase());
});
// this should result in a REFUSED status
if (!myDomains.length) {
// REFUSED will have no records, so we could still recursion, if enabled
results.header.rcode = REFUSED;
cb(null, results);
return;
}
myDomains.sort(function (d1, d2) {
if (d1.id.length > d2.id.length) {
return -1;
}
if (d1.id.length < d2.id.length) {
return 1;
}
return 0;
});
console.log('sorted domains', myDomains);
return getNs(db, myDomains.slice(0), results, function (err, results) {
if (err) { cb(err, results); return; }
// has NS records
if (NXDOMAIN !== results.header.rcode) { cb(null, results); return; }
// myDomains was sorted such that the longest was first
getSoa(db, myDomains[0], results, cb);
});
}
/* /*
query.question.forEach(function (q) { query.question.forEach(function (q) {
module.exports.ask(q); module.exports.ask(q);

61
samples/zones.js Normal file
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@ -0,0 +1,61 @@
'use strict';
module.exports = {
"domain": [
{ "id": "daplie.me", "revokedAt": 0 }
, { "id": "oneal.daplie.me", "revokedAt": 0 }
, { "id": "aj.oneal.daplie.me", "revokedAt": 0 }
]
, "records": [
// zone daplie.me should be able to have some records on its own
{ "zone": "daplie.me", "type": "A", "domain": "www.daplie.me"
, "tld": "me", "sld": "daplie", "sub": "www", "value": "23.228.168.108", "aname": "tardigrade.devices.daplie.me" }
, { "zone": "daplie.me", "type": "CNAME", "domain": "email.daplie.me"
, "tld": "me", "sld": "daplie", "sub": "email", "value": "mailgun.org" }
, { "zone": "daplie.me", "type": "ANAME", "domain": "tardigrade.devices.daplie.me", "device": "abcdef123"
, "tld": "me", "sld": "daplie", "sub": "tardigrade.devices", "value": "23.228.168.108" }
// zone daplie.me can delegate oneal.daplie.me to the same nameserver
// (it's probably programmatically and politically simplest to always delegate from a parent zone)
// Thought Experiment: could we delegate the root to a child? i.e. daplie.me -> www.daplie.me
// to let someone exclusively "own" the root domain, but none of the children?
, { "zone": "daplie.me", "type": "NS", "domain": "oneal.daplie.me"
, "tld": "me", "sld": "daplie", "sub": "oneal", "value": "ns1.redirect-www.org" }
, { "zone": "daplie.me", "type": "NS", "domain": "oneal.daplie.me"
, "tld": "me", "sld": "daplie", "sub": "oneal", "value": "ns2.redirect-www.org" }
//
// now the zone "oneal.daplie.me" can be independently owned (and delegated)
// ... but what about email for aj@daplie.me with aj@daplie.me?
, { "zone": "oneal.daplie.me", "type": "A", "domain": "oneal.daplie.me"
, "tld": "daplie.me", "sld": "oneal", "sub": "", "value": "45.56.59.142", "aname": "leo.devices.oneal.daplie.me" }
, { "zone": "oneal.daplie.me", "type": "CNAME", "domain": "www.oneal.daplie.me"
, "tld": "daplie.me", "sld": "oneal", "sub": "www", "value": "oneal.daplie.me" }
, { "zone": "oneal.daplie.me", "type": "NS", "domain": "aj.oneal.daplie.me"
, "tld": "daplie.me", "sld": "oneal", "sub": "aj", "value": "ns1.redirect-www.org" }
, { "zone": "oneal.daplie.me", "type": "NS", "domain": "aj.oneal.daplie.me"
, "tld": "daplie.me", "sld": "oneal", "sub": "aj", "value": "ns2.redirect-www.org" }
// there can be a wildcard, to which a delegation is the exception
, { "zone": "oneal.daplie.me", "type": "A", "domain": "*.oneal.daplie.me"
, "tld": "daplie.me", "sld": "oneal", "sub": "*", "value": "45.56.59.142", "aname": "leo.devices.oneal.daplie.me" }
// there can be an exception to the delegation
, { "zone": "oneal.daplie.me", "type": "A", "domain": "exception.aj.oneal.daplie.me"
, "tld": "daplie.me", "sld": "oneal", "sub": "exception.aj", "value": "45.56.59.142", "aname": "leo.devices.oneal.daplie.me" }
//
// aj.oneal.daplie.me
//
, { "zone": "aj.oneal.daplie.me", "type": "A", "domain": "aj.oneal.daplie.me"
, "tld": "oneal.daplie.me", "sld": "aj", "sub": "", "value": "45.56.59.142", "aname": "leo.devices.oneal.daplie.me" }
]
}
;