implement the NAPTR record (#89)

* implement the NAPTR record

* implement NAPTR record for readme

* update

* Update index.js

* Update index.js

* Update index.js

* fix test failed

* Add actual example values to README

* Update README.md

* Update README.md

---------

Co-authored-by: root <root@wxs1.fyre.ibm.com>
Co-authored-by: silverwind <me@silverwind.io>

README.md

@@ -366,6 +366,22 @@ The options `PADDING`, `CLIENT_SUBNET`, `TCP_KEEPALIVE` and `KEY_TAG` support en
 }
 ```
 
+#### `NAPTR`
+
+``` js
+{
+  data:
+    {
+      order: 100,
+      preference: 10,
+      flags: 's',
+      services: 'SIP+D2U',
+      regexp: '!^.*$!sip:customer-service@example.com!',
+      replacement: '_sip._udp.example.com'
+    }
+}
+```
+
 When encoding, scalar values are converted to an array and strings are converted to UTF-8 encoded Buffers. When decoding, the return value will always be an array of Buffer.
 
 If you need another record type, open an issue and we'll try to add it.

index.js

@@ -1353,6 +1353,62 @@ rsshfp.encodingLength = function (record) {
   return 4 + Buffer.from(record.fingerprint, 'hex').byteLength
 }
 
+const rnaptr = exports.naptr = {}
+
+rnaptr.encode = function (data, buf, offset) {
+  if (!buf) buf = Buffer.alloc(rnaptr.encodingLength(data))
+  if (!offset) offset = 0
+  const oldOffset = offset
+  offset += 2
+  buf.writeUInt16BE(data.order || 0, offset)
+  offset += 2
+  buf.writeUInt16BE(data.preference || 0, offset)
+  offset += 2
+  string.encode(data.flags, buf, offset)
+  offset += string.encode.bytes
+  string.encode(data.services, buf, offset)
+  offset += string.encode.bytes
+  string.encode(data.regexp, buf, offset)
+  offset += string.encode.bytes
+  name.encode(data.replacement, buf, offset)
+  offset += name.encode.bytes
+  rnaptr.encode.bytes = offset - oldOffset
+  buf.writeUInt16BE(rnaptr.encode.bytes - 2, oldOffset)
+  return buf
+}
+
+rnaptr.encode.bytes = 0
+
+rnaptr.decode = function (buf, offset) {
+  if (!offset) offset = 0
+  const oldOffset = offset
+  const data = {}
+  offset += 2
+  data.order = buf.readUInt16BE(offset)
+  offset += 2
+  data.preference = buf.readUInt16BE(offset)
+  offset += 2
+  data.flags = string.decode(buf, offset)
+  offset += string.decode.bytes
+  data.services = string.decode(buf, offset)
+  offset += string.decode.bytes
+  data.regexp = string.decode(buf, offset)
+  offset += string.decode.bytes
+  data.replacement = name.decode(buf, offset)
+  offset += name.decode.bytes
+  rnaptr.decode.bytes = offset - oldOffset
+  return data
+}
+
+rnaptr.decode.bytes = 0
+
+rnaptr.encodingLength = function (data) {
+  return string.encodingLength(data.flags) +
+    string.encodingLength(data.services) +
+    string.encodingLength(data.regexp) +
+    name.encodingLength(data.replacement) + 6
+}
+
 const renc = exports.record = function (type) {
   switch (type.toUpperCase()) {
     case 'A': return ra
@@ -1376,6 +1432,7 @@ const renc = exports.record = function (type) {
     case 'NSEC3': return rnsec3
     case 'SSHFP': return rsshfp
     case 'DS': return rds
+    case 'NAPTR': return rnaptr
   }
   return runknown
 }

test.js

@@ -556,6 +556,18 @@ tape('ds', function (t) {
   t.end()
 })
 
+tape('naptr', function (t) {
+  testEncoder(t, packet.naptr, {
+    order: 1,
+    preference: 1,
+    flags: 'S',
+    services: 'SIP+D2T',
+    regexp: '!^.*$!sip:customer-service@xuexample.com!',
+    replacement: '_sip._udp.xuexample.com'
+  })
+  t.end()
+})
+
 tape('unpack', function (t) {
   const buf = Buffer.from([
     0x00, 0x79,