From a089bfc8e549a6769e2894f9837f76b4f09d1f1d Mon Sep 17 00:00:00 2001
From: AJ ONeal <aj@daplie.com>
Date: Thu, 12 Oct 2017 12:48:09 -0600
Subject: [PATCH] add ANAME resolution

---
 README.md        |  9 ++++++++
 TESTS.md         |  8 +++++++
 bin/digd.js      |  6 ++++++
 lib/dns-store.js | 56 ++++++++++++++++++++++++++++++++++++++++++++----
 samples/db.js    |  3 +++
 5 files changed, 78 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 95cd154..80c4699 100644
--- a/README.md
+++ b/README.md
@@ -155,6 +155,7 @@ module.exports = {
 
       // A, AAAA
     , address: '127.0.0.1'
+    , aname: 'some-device.example.com' // See "A Note on ANAMEs" below
 
       // CAA
     , flag: 0
@@ -194,6 +195,14 @@ Note: Because it's possible to that delegated subdomains could have delegated su
 original nameserver, **NS** records will be replaced with an SOA record if any of the NS records match any of
 the server's primary nameservers or if vanity nameservers are used.
 
+### A Note on ANAMES
+
+ANAMEs serve two purposes in this system:
+
+1. Traditional ANAME. Just a CNAME that is automatically resolved to an A record for the "bare domain" problem, and efficiency.
+2. Dynamic DNS. When a record on the system is updated, any records that match it by ANAME are also updated
+
+TODO: use dns0x20 for ANAME resolutions
 
 Other Resources
 ---------------
diff --git a/TESTS.md b/TESTS.md
index 27fa1fd..8cffd36 100644
--- a/TESTS.md
+++ b/TESTS.md
@@ -23,8 +23,16 @@ Send malformed packets (both as queries and as answers):
   - compression pointers to wrong bits (throw error on non-ascii / unsafe chars)
 
 Test that ANY queries return records of all types matching the domain
+
 Test that A queries only return A records, not others matching the domain
 
+Test that A queries for ANAME-enabled records (but no address) recurse (regardless of general recursion settings).
+  * 0-anames.example.com
+  * 1-aname.example.com
+  * 2-anames.example.com
+
+Generally speaking test the cases of 0, 1, and 2 records of any given type (null case, single case, multi case)
+
 
 ```
 # Sample Data:
diff --git a/bin/digd.js b/bin/digd.js
index 727102c..c7baad0 100755
--- a/bin/digd.js
+++ b/bin/digd.js
@@ -367,6 +367,12 @@ cli.main(function (args, cli) {
 
     // TODO get local answer first, if available
     var path = require('path');
+    if (!cli.input) {
+      console.warn('[WARN] no db path given, must recurse if enabled');
+      recurse();
+      return;
+    }
+
     require('../lib/dns-store').query(path.resolve(cli.input), query, function (err, resp) {
 
       if (err) { console.log('[DEV] answer not found in local db, recursing'); console.error(err); recurse(); return; }
diff --git a/lib/dns-store.js b/lib/dns-store.js
index 738ab38..b42b30a 100644
--- a/lib/dns-store.js
+++ b/lib/dns-store.js
@@ -11,7 +11,12 @@ var NXDOMAIN = 3;
 var REFUSED = 5;
 
 function getRecords(db, qname, cb) {
-  var myRecords = db.records.filter(function (r) {
+  var delMe = {};
+  var dns = require('dns');
+  // SECURITY XXX TODO var dig = require('dig.js/dns-request');
+  var count;
+  var myRecords = db.records.slice(0).filter(function (r) {
+
     if ('string' !== typeof r.name) {
       return false;
     }
@@ -23,9 +28,52 @@ function getRecords(db, qname, cb) {
     }
   });
 
-  process.nextTick(function () {
-    cb(null, myRecords);
+  function checkCount() {
+    count -= 1;
+    if (count <= 0) {
+      myRecords = myRecords.filter(function (r) {
+        return !delMe[r.id];
+      });
+      cb(null, myRecords);
+    }
+  }
+
+  function getRecord(r) {
+    // TODO allow multiple records to be returned(?)
+    return function (err, addresses) {
+      if (err || !addresses.length) {
+        r.id = r.id || Math.random();
+        delMe[r.id] = true;
+      } else if (addresses.length > 1) {
+        r._address = addresses[Math.floor(Math.random() * addresses.length)];
+      } else {
+        r._address = addresses[0];
+      }
+      checkCount();
+    };
+  }
+
+  count = myRecords.length;
+  myRecords.forEach(function (r) {
+    if (r.aname && !r.address) {
+      if ('A' === r.type) {
+        // SECURITY XXX TODO dig.resolveJson(query, opts);
+        dns.resolve4(r.aname, getRecord(r));
+        return;
+      }
+      if ('AAAA' === r.type) {
+        // SECURITY XXX TODO dig.resolveJson(query, opts);
+        dns.resolve6(r.aname, getRecord(r));
+        return;
+      }
+    }
+
+    checkCount();
   });
+
+  if (!myRecords.length) {
+    checkCount();
+  }
 }
 
 function dbToResourceRecord(r) {
@@ -47,7 +95,7 @@ function dbToResourceRecord(r) {
     */
 
     // A, AAAA
-  , address: -1 !== [ 'A', 'AAAA' ].indexOf(r.type) ? (r.address || r.value) : undefined
+  , address: -1 !== [ 'A', 'AAAA' ].indexOf(r.type) ? (r._address || r.address || r.value) : undefined
 
     // CNAME, NS, PTR || TXT
   , data: -1 !== [ 'CNAME', 'NS', 'PTR', 'TXT' ].indexOf(r.type) ? (r.data || r.value || r.values) : undefined
diff --git a/samples/db.js b/samples/db.js
index 46d3db9..9b328ea 100644
--- a/samples/db.js
+++ b/samples/db.js
@@ -15,6 +15,9 @@ module.exports = {
   , { "zone": "daplie.me", "name": "www.daplie.me", "tld": "me", "sld": "daplie", "sub": "www"
     , "type": "A", "address": "23.228.168.108", "aname": "tardigrade.devices.daplie.me" }
 
+  , { "zone": "daplie.me", "name": "aname.daplie.me", "tld": "me", "sld": "daplie", "sub": "aname"
+    , "type": "A", "aname": "google.com" }
+
   , { "zone": "daplie.me", "name": "email.daplie.me", "tld": "me", "sld": "daplie", "sub": "email"
     , "type": "CNAME", "data": "mailgun.org" }