more

CHANGES.md

@@ -8,6 +8,9 @@
 - zone_opts, for influencing output of toBind
 - normalize hostnames to lower case
 - add tests: fullyQualify, getFQDN
+- AAAA.compress: rewrote per RFC 5952, added tests
+- AAAA: internally store address in expanded notation
+- fromTinydns: apply correct semantics for 'x' handling
 
 
 #### 0.9.3 - 2022-03-22

lib/tinydns.js

@@ -1,7 +1,7 @@
 
 const SPECIALCHARS = {
   '+': [ 'A' ],
-  '-': [ undefined ],
+  '-': [ undefined ],  // disabled RR
   '%': [ 'location' ],
   '.': [ 'SOA', 'NS', 'A' ],
   '&': [ 'NS', 'A' ],

rr/aaaa.js

@@ -12,9 +12,9 @@ class AAAA extends RR {
   /****** Resource record specific setters   *******/
   setAddress (val) {
     if (!val) throw new Error('AAAA: address is required')
-    if (!net.isIPv6(val)) throw new Error('AAAA: address must be IPv6')
+    if (!net.isIPv6(val)) throw new Error(`AAAA: address must be IPv6 (${val})`)
 
-    this.set('address', val.toLowerCase()) // IETFs suggest only lower case
+    this.set('address', this.expand(val.toLowerCase())) // lower case: RFC 5952
   }
 
   getCompressed (val) {
@@ -45,14 +45,13 @@ class AAAA extends RR {
       case ':':
         // GENERIC  =>  :fqdn:28:rdata:ttl:timestamp:lo
         [ fqdn, n, rdata, ttl, ts, loc ] = str.substring(1).split(':')
-        if (n != 28) throw new Error('SRV fromTinydns, invalid n')
-        // compressed format is needed for test comparisons
-        ip = this.compress(TINYDNS.octalToHex(rdata).match(/([0-9a-fA-F]{4})/g).join(':'))
+        if (n != 28) throw new Error('AAAA fromTinydns, invalid n')
+        ip = TINYDNS.octalToHex(rdata).match(/([0-9a-fA-F]{4})/g).join(':')
         break
       case '3':
       case '6':
-        // AAAA     =>  3 fqdn:rdata:x:ttl:timestamp:lo
-        // AAAA,PTR =>  6 fqdn:rdata:x:ttl:timestamp:lo
+        // AAAA     =>  3fqdn:ip:x:ttl:timestamp:lo
+        // AAAA,PTR =>  6fqdn:ip:x:ttl:timestamp:lo
         [ fqdn, rdata, ttl, ts, loc ] = str.substring(1).split(':')
         ip = rdata.match(/(.{4})/g).join(':')
         break
@@ -75,17 +74,40 @@ class AAAA extends RR {
       class  : c,
       type   : type,
       name   : fqdn,
-      address: ip,
+      address: this.expand(ip),
       ttl    : parseInt(ttl, 10),
     })
   }
 
   compress (val) {
-    return val
-      .replace(/\b(?:0+:){2,}/, ':')  // compress all zero
-      .split(':')
-      .map(o => o.replace(/\b0+/g, '')) // strip leading zero
-      .join(':')
+    /*
+     * RFC 5952
+     * 4.1. Leading zeros MUST be suppressed...A single 16-bit 0000 field MUST be represented as 0.
+     * 4.2.1 The use of the symbol "::" MUST be used to its maximum capability.
+     * 4.2.2 The symbol "::" MUST NOT be used to shorten just one 16-bit 0 field.
+     * 4.2.3 When choosing placement of a "::", the longest run...MUST be shortened
+     * 4.3 The characters a-f in an IPv6 address MUST be represented in lowercase.
+    */
+    let r = val
+      .replace(/0000/g, '0')             // 4.1 0000 -> 0
+      .replace(/:0+([1-9a-f])/g, ':$1')  // 4.1 remove leading zeros
+
+    const mostConsecutiveZeros = [
+      new RegExp(/0?(?::0){6,}:0?/),
+      new RegExp(/0?(?::0){5,}:0?/),
+      new RegExp(/0?(?::0){4,}:0?/),
+      new RegExp(/0?(?::0){3,}:0?/),
+      new RegExp(/0?(?::0){2,}:0?/),
+    ]
+
+    for (const re of mostConsecutiveZeros) {
+      if (re.test(r)) {
+        r = r.replace(re, '::')
+        break
+      }
+    }
+
+    return r
   }
 
   expand (val, delimiter) {
@@ -102,6 +124,9 @@ class AAAA extends RR {
   }
 
   /******  EXPORTERS   *******/
+  toBind (zone_opts) {
+    return `${this.getPrefix(zone_opts)}\t${this.compress(this.get('address'))}\n`
+  }
 
   toTinydns () {
     // from AAAA notation (8 groups of 4 hex digits) to 16 escaped octals

rr/index.js

@@ -112,10 +112,11 @@ class RR extends Map {
     this.set('type', t)
   }
 
-  fullyQualify (str) {
-    if (!str) return str
-    if (str.endsWith('.')) return str
-    return `${str}.`
+  fullyQualify (hostname, origin) {
+    if (!hostname) return hostname
+    if (hostname.endsWith('.')) return hostname.toLowerCase()
+    if (origin) return `${hostname}.${origin}`.toLowerCase()
+    return `${hostname}.`
   }
 
   getPrefix (zone_opts = {}) {
@@ -265,6 +266,7 @@ class RR extends Map {
 
 module.exports = {
   RR,
+  TINYDNS: require('../lib/tinydns'),
 }
 
 const files = fs.readdirSync(path.join(__dirname))

rr/mx.js

@@ -52,7 +52,7 @@ class MX extends RR {
     return new this.constructor({
       type      : 'MX',
       name      : this.fullyQualify(fqdn),
-      exchange  : this.fullyQualify(x),
+      exchange  : this.fullyQualify(/\./.test(x) ? x : `${x}.mx.${fqdn}`),
       preference: parseInt(preference, 10) || 0,
       ttl       : parseInt(ttl, 10),
       timestamp : ts,

rr/ns.js

@@ -42,7 +42,7 @@ class NS extends RR {
     return new this.constructor({
       type     : 'NS',
       name     : this.fullyQualify(fqdn),
-      dname    : this.fullyQualify(dname),
+      dname    : this.fullyQualify(/\./.test(dname) ? dname : `${dname}.ns.${fqdn}`),
       ttl      : parseInt(ttl, 10),
       timestamp: ts,
       location : loc !== '' && loc !== '\n' ? loc : '',

test/aaaa.js

@@ -9,7 +9,7 @@ const validRecords = [
     class  : 'IN',
     name   : 'test.example.com.',
     type   : 'AAAA',
-    address: '2001:db8:20:a::4',
+    address: '2001:0db8:0020:000a:0000:0000:0000:0004',
     ttl    : 3600,
     testB  : 'test.example.com.\t3600\tIN\tAAAA\t2001:db8:20:a::4\n',
     testT  : ':test.example.com:28:\\040\\001\\015\\270\\000\\040\\000\\012\\000\\000\\000\\000\\000\\000\\000\\004:3600::\n',
@@ -50,4 +50,30 @@ describe('AAAA record', function () {
       }
     })
   }
+
+  const tests = [
+    { e: '2001:0db8:0020:000a:0000:0000:0000:0004', c: '2001:db8:20:a::4' },
+    { e: '0000:0000:0000:0000:0000:0000:0000:0000', c: '::' },
+    { e: '0000:0000:0000:0000:0000:0000:0000:0001', c: '::1' },
+    { e: '2001:0db8:0000:0000:0000:0000:0002:0001', c: '2001:db8::2:1' },
+    { e: '2001:0db8:0000:0001:0001:0001:0001:0001', c: '2001:db8:0:1:1:1:1:1' },
+  ]
+
+  describe('compress', function () {
+    const r = new AAAA(null)
+    for (const t of tests) {
+      it(`compresses IPv6 address (${t.e})`, function () {
+        assert.equal(r.compress(t.e), t.c)
+      })
+    }
+  })
+
+  describe('expand', function () {
+    const r = new AAAA(null)
+    for (const t of tests) {
+      it(`expands IPv6 address (${t.c})`, function () {
+        assert.equal(r.expand(t.c), t.e)
+      })
+    }
+  })
 })

test/tinydns.js

@@ -27,6 +27,12 @@ describe('TINYDNS', function () {
     }
   })
 
+  describe('octalToHex', function () {
+    it('unescapes octal to hex digits', function () {
+      assert.strictEqual(TINYDNS.octalToHex('\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\001'), '00000000000000000000000000000001')
+    })
+  })
+
   describe('UInt16toOctal', function () {
     it('converts a 16-bit number to escaped octal', function () {
       assert.strictEqual(TINYDNS.UInt16toOctal(65535), '\\377\\377')