var types = require('./types')
var rcodes = require('./rcodes')
var opcodes = require('./opcodes')
var ip = require('ip')
var Buffer = require('safe-buffer').Buffer
var QUERY_FLAG = 0
var RESPONSE_FLAG = 1 << 15
var FLUSH_MASK = 1 << 15
var NOT_FLUSH_MASK = ~FLUSH_MASK
var QU_MASK = 1 << 15
var NOT_QU_MASK = ~QU_MASK
var name = exports.txt = exports.name = {}
name.encode = function (str, buf, offset) {
if (!buf) buf = Buffer.alloc(name.encodingLength(str))
if (!offset) offset = 0
var oldOffset = offset
// strip leading and trailing .
var n = str.replace(/^\.|\.$/gm, '')
if (n.length) {
var list = n.split('.')
for (var i = 0; i < list.length; i++) {
var len = buf.write(list[i], offset + 1)
buf[offset] = len
offset += len + 1
}
}
buf[offset++] = 0
name.encode.bytes = offset - oldOffset
return buf
}
name.encode.bytes = 0
name.decode = function (buf, offset) {
if (!offset) offset = 0
var list = []
var oldOffset = offset
var len = buf[offset++]
if (len === 0) {
name.decode.bytes = 1
return '.'
}
if (len >= 0xc0) {
var res = name.decode(buf, buf.readUInt16BE(offset - 1) - 0xc000)
name.decode.bytes = 2
return res
}
while (len) {
if (len >= 0xc0) {
list.push(name.decode(buf, buf.readUInt16BE(offset - 1) - 0xc000))
offset++
break
}
list.push(buf.toString('utf-8', offset, offset + len))
offset += len
len = buf[offset++]
}
name.decode.bytes = offset - oldOffset
return list.join('.')
}
name.decode.bytes = 0
name.encodingLength = function (n) {
if (n === '.' || n === '..') return 1
return Buffer.byteLength(n.replace(/^\.|\.$/gm, '')) + 2
}
var string = {}
string.encode = function (s, buf, offset) {
if (!buf) buf = Buffer.alloc(string.encodingLength(s))
if (!offset) offset = 0
var len = buf.write(s, offset + 1)
buf[offset] = len
string.encode.bytes = len + 1
return buf
}
string.encode.bytes = 0
string.decode = function (buf, offset) {
if (!offset) offset = 0
var len = buf[offset]
var s = buf.toString('utf-8', offset + 1, offset + 1 + len)
string.decode.bytes = len + 1
return s
}
string.decode.bytes = 0
string.encodingLength = function (s) {
return Buffer.byteLength(s) + 1
}
var header = {}
header.encode = function (h, buf, offset) {
if (!buf) buf = header.encodingLength(h)
if (!offset) offset = 0
var flags = (h.flags || 0) & 32767
var type = h.type === 'response' ? RESPONSE_FLAG : QUERY_FLAG
buf.writeUInt16BE(h.id || 0, offset)
buf.writeUInt16BE(flags | type, offset + 2)
buf.writeUInt16BE(h.questions.length, offset + 4)
buf.writeUInt16BE(h.answers.length, offset + 6)
buf.writeUInt16BE(h.authorities.length, offset + 8)
buf.writeUInt16BE(h.additionals.length, offset + 10)
return buf
}
header.encode.bytes = 12
header.decode = function (buf, offset) {
if (!offset) offset = 0
if (buf.length < 12) throw new Error('Header must be 12 bytes')
var flags = buf.readUInt16BE(offset + 2)
return {
id: buf.readUInt16BE(offset),
type: flags & RESPONSE_FLAG ? 'response' : 'query',
flags: flags & 32767,
flag_qr: ((flags >> 15) & 0x1) === 1,
opcode: opcodes.toString((flags >> 11) & 0xf),
flag_auth: ((flags >> 10) & 0x1) === 1,
flag_trunc: ((flags >> 9) & 0x1) === 1,
flag_rd: ((flags >> 8) & 0x1) === 1,
flag_ra: ((flags >> 7) & 0x1) === 1,
flag_z: ((flags >> 6) & 0x1) === 1,
flag_ad: ((flags >> 5) & 0x1) === 1,
flag_cd: ((flags >> 4) & 0x1) === 1,
rcode: rcodes.toString(flags & 0xf),
questions: new Array(buf.readUInt16BE(offset + 4)),
answers: new Array(buf.readUInt16BE(offset + 6)),
authorities: new Array(buf.readUInt16BE(offset + 8)),
additionals: new Array(buf.readUInt16BE(offset + 10))
}
}
header.decode.bytes = 12
header.encodingLength = function () {
return 12
}
var runknown = exports.unknown = {}
runknown.encode = function (data, buf, offset) {
if (!buf) buf = Buffer.alloc(runknown.encodingLength(data))
if (!offset) offset = 0
buf.writeUInt16BE(data.length, offset)
data.copy(buf, offset + 2)
runknown.encode.bytes = data.length + 2
return buf
}
runknown.encode.bytes = 0
runknown.decode = function (buf, offset) {
if (!offset) offset = 0
var len = buf.readUInt16BE(offset)
var data = buf.slice(offset + 2, offset + 2 + len)
runknown.decode.bytes = len + 2
return data
}
runknown.decode.bytes = 0
runknown.encodingLength = function (data) {
return data.length + 2
}
var rns = exports.ns = {}
rns.encode = function (data, buf, offset) {
if (!buf) buf = Buffer.alloc(rns.encodingLength(data))
if (!offset) offset = 0
name.encode(data, buf, offset + 2)
buf.writeUInt16BE(name.encode.bytes, offset)
rns.encode.bytes = name.encode.bytes + 2
return buf
}
rns.encode.bytes = 0
rns.decode = function (buf, offset) {
if (!offset) offset = 0
var len = buf.readUInt16BE(offset)
var dd = name.decode(buf, offset + 2)
rns.decode.bytes = len + 2
return dd
}
rns.decode.bytes = 0
rns.encodingLength = function (data) {
return name.encodingLength(data) + 2
}
var rsoa = exports.soa = {}
rsoa.encode = function (data, buf, offset) {
if (!buf) buf = Buffer.alloc(rsoa.encodingLength(data))
if (!offset) offset = 0
var oldOffset = offset
offset += 2
name.encode(data.mname, buf, offset)
offset += name.encode.bytes
name.encode(data.rname, buf, offset)
offset += name.encode.bytes
buf.writeUInt32BE(data.serial || 0, offset)
offset += 4
buf.writeUInt32BE(data.refresh || 0, offset)
offset += 4
buf.writeUInt32BE(data.retry || 0, offset)
offset += 4
buf.writeUInt32BE(data.expire || 0, offset)
offset += 4
buf.writeUInt32BE(data.minimum || 0, offset)
offset += 4
buf.writeUInt16BE(offset - oldOffset - 2, oldOffset)
rsoa.encode.bytes = offset - oldOffset
return buf
}
rsoa.encode.bytes = 0
rsoa.decode = function (buf, offset) {
if (!offset) offset = 0
var oldOffset = offset
var data = {}
offset += 2
data.mname = name.decode(buf, offset)
offset += name.decode.bytes
data.rname = name.decode(buf, offset)
offset += name.decode.bytes
data.serial = buf.readUInt32BE(offset)
offset += 4
data.refresh = buf.readUInt32BE(offset)
offset += 4
data.retry = buf.readUInt32BE(offset)
offset += 4
data.expire = buf.readUInt32BE(offset)
offset += 4
data.minimum = buf.readUInt32BE(offset)
offset += 4
rsoa.decode.bytes = offset - oldOffset
return data
}
rsoa.decode.bytes = 0
rsoa.encodingLength = function (data) {
return 22 + name.encodingLength(data.mname) + name.encodingLength(data.rname)
}
var rtxt = exports.txt = exports.null = {}
var rnull = rtxt
rtxt.encode = function (data, buf, offset) {
if (!buf) buf = Buffer.alloc(rtxt.encodingLength(data))
if (!offset) offset = 0
if (typeof data === 'string') data = Buffer.from(data)
if (!data) data = Buffer.alloc(0)
var oldOffset = offset
offset += 2
var len = data.length
data.copy(buf, offset, 0, len)
offset += len
buf.writeUInt16BE(offset - oldOffset - 2, oldOffset)
rtxt.encode.bytes = offset - oldOffset
return buf
}
rtxt.encode.bytes = 0
rtxt.decode = function (buf, offset) {
if (!offset) offset = 0
var oldOffset = offset
var len = buf.readUInt16BE(offset)
offset += 2
var data = buf.slice(offset, offset + len)
offset += len
rtxt.decode.bytes = offset - oldOffset
return data
}
rtxt.decode.bytes = 0
rtxt.encodingLength = function (data) {
if (!data) return 2
return (Buffer.isBuffer(data) ? data.length : Buffer.byteLength(data)) + 2
}
var rhinfo = exports.hinfo = {}
rhinfo.encode = function (data, buf, offset) {
if (!buf) buf = Buffer.alloc(rhinfo.encodingLength(data))
if (!offset) offset = 0
var oldOffset = offset
offset += 2
string.encode(data.cpu, buf, offset)
offset += string.encode.bytes
string.encode(data.os, buf, offset)
offset += string.encode.bytes
buf.writeUInt16BE(offset - oldOffset - 2, oldOffset)
rhinfo.encode.bytes = offset - oldOffset
return buf
}
rhinfo.encode.bytes = 0
rhinfo.decode = function (buf, offset) {
if (!offset) offset = 0
var oldOffset = offset
var data = {}
offset += 2
data.cpu = string.decode(buf, offset)
offset += string.decode.bytes
data.os = string.decode(buf, offset)
offset += string.decode.bytes
rhinfo.decode.bytes = offset - oldOffset
return data
}
rhinfo.decode.bytes = 0
rhinfo.encodingLength = function (data) {
return string.encodingLength(data.cpu) + string.encodingLength(data.os) + 2
}
var rptr = exports.ptr = {}
var rcname = exports.cname = rptr
var rdname = exports.dname = rptr
rptr.encode = function (data, buf, offset) {
if (!buf) buf = Buffer.alloc(rptr.encodingLength(data))
if (!offset) offset = 0
name.encode(data, buf, offset + 2)
buf.writeUInt16BE(name.encode.bytes, offset)
rptr.encode.bytes = name.encode.bytes + 2
return buf
}
rptr.encode.bytes = 0
rptr.decode = function (buf, offset) {
if (!offset) offset = 0
var data = name.decode(buf, offset + 2)
rptr.decode.bytes = name.decode.bytes + 2
return data
}
rptr.decode.bytes = 0
rptr.encodingLength = function (data) {
return name.encodingLength(data) + 2
}
var rsrv = exports.srv = {}
rsrv.encode = function (data, buf, offset) {
if (!buf) buf = Buffer.alloc(rsrv.encodingLength(data))
if (!offset) offset = 0
buf.writeUInt16BE(data.priority || 0, offset + 2)
buf.writeUInt16BE(data.weight || 0, offset + 4)
buf.writeUInt16BE(data.port || 0, offset + 6)
name.encode(data.target, buf, offset + 8)
var len = name.encode.bytes + 6
buf.writeUInt16BE(len, offset)
rsrv.encode.bytes = len + 2
return buf
}
rsrv.encode.bytes = 0
rsrv.decode = function (buf, offset) {
if (!offset) offset = 0
var len = buf.readUInt16BE(offset)
var data = {}
data.priority = buf.readUInt16BE(offset + 2)
data.weight = buf.readUInt16BE(offset + 4)
data.port = buf.readUInt16BE(offset + 6)
data.target = name.decode(buf, offset + 8)
rsrv.decode.bytes = len + 2
return data
}
rsrv.decode.bytes = 0
rsrv.encodingLength = function (data) {
return 8 + name.encodingLength(data.target)
}
var rcaa = exports.caa = {}
rcaa.ISSUER_CRITICAL = 1 << 7
rcaa.encode = function (data, buf, offset) {
var len = rcaa.encodingLength(data)
if (!buf) buf = Buffer.alloc(rcaa.encodingLength(data))
if (!offset) offset = 0
if (data.issuerCritical) {
data.flags = rcaa.ISSUER_CRITICAL
}
buf.writeUInt16BE(len - 2, offset)
offset += 2
buf.writeUInt8(data.flags || 0, offset)
offset += 1
string.encode(data.tag, buf, offset)
offset += string.encode.bytes
buf.write(data.value, offset)
offset += Buffer.byteLength(data.value)
rcaa.encode.bytes = len
return buf
}
rcaa.encode.bytes = 0
rcaa.decode = function (buf, offset) {
if (!offset) offset = 0
var len = buf.readUInt16BE(offset)
offset += 2
var oldOffset = offset
var data = {}
data.flags = buf.readUInt8(offset)
offset += 1
data.tag = string.decode(buf, offset)
offset += string.decode.bytes
data.value = buf.toString('utf-8', offset, oldOffset + len)
data.issuerCritical = !!(data.flags & rcaa.ISSUER_CRITICAL)
rcaa.decode.bytes = len + 2
return data
}
rcaa.decode.bytes = 0
rcaa.encodingLength = function (data) {
return string.encodingLength(data.tag) + string.encodingLength(data.value) + 2
}
var ra = exports.a = {}
ra.encode = function (host, buf, offset) {
if (!buf) buf = Buffer.alloc(ra.encodingLength(host))
if (!offset) offset = 0
buf.writeUInt16BE(4, offset)
offset += 2
ip.toBuffer(host, buf, offset)
ra.encode.bytes = 6
return buf
}
ra.encode.bytes = 0
ra.decode = function (buf, offset) {
if (!offset) offset = 0
offset += 2
var host = ip.toString(buf, offset, 4)
ra.decode.bytes = 6
return host
}
ra.decode.bytes = 0
ra.encodingLength = function () {
return 6
}
var raaaa = exports.aaaa = {}
raaaa.encode = function (host, buf, offset) {
if (!buf) buf = Buffer.alloc(raaaa.encodingLength(host))
if (!offset) offset = 0
buf.writeUInt16BE(16, offset)
offset += 2
ip.toBuffer(host, buf, offset)
raaaa.encode.bytes = 18
return buf
}
raaaa.encode.bytes = 0
raaaa.decode = function (buf, offset) {
if (!offset) offset = 0
offset += 2
var host = ip.toString(buf, offset, 16)
raaaa.decode.bytes = 18
return host
}
raaaa.decode.bytes = 0
raaaa.encodingLength = function () {
return 18
}
var renc = exports.record = function (type) {
switch (type.toUpperCase()) {
case 'A': return ra
case 'PTR': return rptr
case 'CNAME': return rcname
case 'DNAME': return rdname
case 'TXT': return rtxt
case 'NULL': return rnull
case 'AAAA': return raaaa
case 'SRV': return rsrv
case 'HINFO': return rhinfo
case 'CAA': return rcaa
case 'NS': return rns
case 'SOA': return rsoa
}
return runknown
}
var answer = exports.answer = {}
answer.encode = function (a, buf, offset) {
if (!buf) buf = Buffer.alloc(answer.encodingLength(a))
if (!offset) offset = 0
var oldOffset = offset
name.encode(a.name, buf, offset)
offset += name.encode.bytes
buf.writeUInt16BE(types.toType(a.type), offset)
var klass = a.class === undefined ? 1 : a.class
if (a.flush) klass |= FLUSH_MASK // the 1st bit of the class is the flush bit
buf.writeUInt16BE(klass, offset + 2)
buf.writeUInt32BE(a.ttl || 0, offset + 4)
var enc = renc(a.type)
enc.encode(a.data, buf, offset + 8)
offset += 8 + enc.encode.bytes
answer.encode.bytes = offset - oldOffset
return buf
}
answer.encode.bytes = 0
answer.decode = function (buf, offset) {
if (!offset) offset = 0
var a = {}
var oldOffset = offset
a.name = name.decode(buf, offset)
offset += name.decode.bytes
a.type = types.toString(buf.readUInt16BE(offset))
a.class = buf.readUInt16BE(offset + 2)
a.ttl = buf.readUInt32BE(offset + 4)
a.flush = !!(a.class & FLUSH_MASK)
if (a.flush) a.class &= NOT_FLUSH_MASK
var enc = renc(a.type)
a.data = enc.decode(buf, offset + 8)
offset += 8 + enc.decode.bytes
answer.decode.bytes = offset - oldOffset
return a
}
answer.decode.bytes = 0
answer.encodingLength = function (a) {
return name.encodingLength(a.name) + 8 + renc(a.type).encodingLength(a.data)
}
var question = exports.question = {}
question.encode = function (q, buf, offset) {
if (!buf) buf = Buffer.alloc(question.encodingLength(q))
if (!offset) offset = 0
var oldOffset = offset
name.encode(q.name, buf, offset)
offset += name.encode.bytes
buf.writeUInt16BE(types.toType(q.type), offset)
offset += 2
buf.writeUInt16BE(q.class === undefined ? 1 : q.class, offset)
offset += 2
question.encode.bytes = offset - oldOffset
return q
}
question.encode.bytes = 0
question.decode = function (buf, offset) {
if (!offset) offset = 0
var oldOffset = offset
var q = {}
q.name = name.decode(buf, offset)
offset += name.decode.bytes
q.type = types.toString(buf.readUInt16BE(offset))
offset += 2
q.class = buf.readUInt16BE(offset)
offset += 2
var qu = !!(q.class & QU_MASK)
if (qu) q.class &= NOT_QU_MASK
question.decode.bytes = offset - oldOffset
return q
}
question.decode.bytes = 0
question.encodingLength = function (q) {
return name.encodingLength(q.name) + 4
}
exports.AUTHORITATIVE_ANSWER = 1 << 10
exports.TRUNCATED_RESPONSE = 1 << 9
exports.RECURSION_DESIRED = 1 << 8
exports.RECURSION_AVAILABLE = 1 << 7
exports.AUTHENTIC_DATA = 1 << 5
exports.CHECKING_DISABLED = 1 << 4
exports.encode = function (result, buf, offset) {
var allocing = !buf
if (allocing) buf = Buffer.alloc(exports.encodingLength(result))
if (!offset) offset = 0
var oldOffset = offset
if (!result.questions) result.questions = []
if (!result.answers) result.answers = []
if (!result.authorities) result.authorities = []
if (!result.additionals) result.additionals = []
header.encode(result, buf, offset)
offset += header.encode.bytes
offset = encodeList(result.questions, question, buf, offset)
offset = encodeList(result.answers, answer, buf, offset)
offset = encodeList(result.authorities, answer, buf, offset)
offset = encodeList(result.additionals, answer, buf, offset)
exports.encode.bytes = offset - oldOffset
// just a quick sanity check
if (allocing && exports.encode.bytes !== buf.length) {
return buf.slice(0, exports.encode.bytes)
}
return buf
}
exports.encode.bytes = 0
exports.decode = function (buf, offset) {
if (!offset) offset = 0
var oldOffset = offset
var result = header.decode(buf, offset)
offset += header.decode.bytes
offset = decodeList(result.questions, question, buf, offset)
offset = decodeList(result.answers, answer, buf, offset)
offset = decodeList(result.authorities, answer, buf, offset)
offset = decodeList(result.additionals, answer, buf, offset)
exports.decode.bytes = offset - oldOffset
return result
}
exports.decode.bytes = 0
exports.encodingLength = function (result) {
return header.encodingLength(result) +
encodingLengthList(result.questions || [], question) +
encodingLengthList(result.answers || [], answer) +
encodingLengthList(result.authorities || [], answer) +
encodingLengthList(result.additionals || [], answer)
}
function encodingLengthList (list, enc) {
var len = 0
for (var i = 0; i < list.length; i++) len += enc.encodingLength(list[i])
return len
}
function encodeList (list, enc, buf, offset) {
for (var i = 0; i < list.length; i++) {
enc.encode(list[i], buf, offset)
offset += enc.encode.bytes
}
return offset
}
function decodeList (list, enc, buf, offset) {
for (var i = 0; i < list.length; i++) {
list[i] = enc.decode(buf, offset)
offset += enc.decode.bytes
}
return offset
}