LittleChest/dns-packet-polyfill
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Decode RCODE and other header flags. Fixes #11.

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This commit is contained in:
Tom Pusateri 2018-01-05 12:46:20 -05:00
parent 5aaf0790d9
commit eabaaa5156
3 changed files with 60 additions and 1 deletions
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10
index.js
View File

@ -1,4 +1,5 @@
var types = require('./types') var types = require('./types')
var rcodes = require('./rcodes')
var ip = require('ip') var ip = require('ip')
var Buffer = require('safe-buffer').Buffer var Buffer = require('safe-buffer').Buffer
@ -126,6 +127,15 @@ header.decode = function (buf, offset) {
id: buf.readUInt16BE(offset), id: buf.readUInt16BE(offset),
type: flags & RESPONSE_FLAG ? 'response' : 'query', type: flags & RESPONSE_FLAG ? 'response' : 'query',
flags: flags & 32767, flags: flags & 32767,
opcode: (flags >> 11) & 0xf,
flag_auth: (flags >> 10) & 0x1,
flag_trunc: (flags >> 9) & 0x1,
flag_rd: (flags >> 8) & 0x1,
flag_ra: (flags >> 7) & 0x1,
flag_z: (flags >> 6) & 0x1,
flag_ad: (flags >> 5) & 0x1,
flag_cd: (flags >> 4) & 0x1,
rcode: rcodes.toString(flags & 0xf),
questions: new Array(buf.readUInt16BE(offset + 4)), questions: new Array(buf.readUInt16BE(offset + 4)),
answers: new Array(buf.readUInt16BE(offset + 6)), answers: new Array(buf.readUInt16BE(offset + 6)),
authorities: new Array(buf.readUInt16BE(offset + 8)), authorities: new Array(buf.readUInt16BE(offset + 8)),

3
package.json
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@ -32,7 +32,8 @@
], ],
"files": [ "files": [
"index.js", "index.js",
"types.js" "types.js",
"rcodes.js"
], ],
"author": "Mathias Buus", "author": "Mathias Buus",
"license": "MIT" "license": "MIT"

48
rcodes.js Normal file
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@ -0,0 +1,48 @@
/*
* Traditional DNS header RCODEs (4-bits) defined by IANA in
* https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml
*/
exports.toString = function (rcode) {
switch (rcode) {
case 0: return 'NOERROR'
case 1: return 'FORMERR'
case 2: return 'SERVFAIL'
case 3: return 'NXDOMAIN'
case 4: return 'NOTIMP'
case 5: return 'REFUSED'
case 6: return 'YXDOMAIN'
case 7: return 'YXRRSET'
case 8: return 'NXRRSET'
case 9: return 'NOTAUTH'
case 10: return 'NOTZONE'
case 11: return 'RCODE_11'
case 12: return 'RCODE_12'
case 13: return 'RCODE_13'
case 14: return 'RCODE_14'
case 15: return 'RCODE_15'
}
return 'RCODE_' + type
}
exports.toRcode = function (code) {
switch (code.toUpperCase()) {
case 'NOERROR': return 0
case 'FORMERR': return 1
case 'SERVFAIL': return 2
case 'NXDOMAIN': return 3
case 'NOTIMP': return 4
case 'REFUSED': return 5
case 'YXDOMAIN': return 6
case 'YXRRSET': return 7
case 'NXRRSET': return 8
case 'NOTAUTH': return 9
case 'NOTZONE': return 10
case 'RCODE_11': return 11
case 'RCODE_12': return 12
case 'RCODE_13': return 13
case 'RCODE_14': return 14
case 'RCODE_15': return 15
}
return 0
}