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diff --git a/testing/xpcshell/dns-packet/README.md b/testing/xpcshell/dns-packet/README.md new file mode 100644 index 0000000000..2a729b3d10 --- /dev/null +++ b/testing/xpcshell/dns-packet/README.md @@ -0,0 +1,365 @@ +# dns-packet +[](https://www.npmjs.org/package/dns-packet) [](https://www.npmjs.org/package/dns-packet) [](https://travis-ci.org/mafintosh/dns-packet) [](https://coveralls.io/github/mafintosh/dns-packet?branch=master) + +An [abstract-encoding](https://github.com/mafintosh/abstract-encoding) compliant module for encoding / decoding DNS packets. Lifted out of [multicast-dns](https://github.com/mafintosh/multicast-dns) as a separate module. + +``` +npm install dns-packet +``` + +## UDP Usage + +``` js +const dnsPacket = require('dns-packet') +const dgram = require('dgram') + +const socket = dgram.createSocket('udp4') + +const buf = dnsPacket.encode({ + type: 'query', + id: 1, + flags: dnsPacket.RECURSION_DESIRED, + questions: [{ + type: 'A', + name: 'google.com' + }] +}) + +socket.on('message', message => { + console.log(dnsPacket.decode(message)) // prints out a response from google dns +}) + +socket.send(buf, 0, buf.length, 53, '8.8.8.8') +``` + +Also see [the UDP example](examples/udp.js). + +## TCP, TLS, HTTPS + +While DNS has traditionally been used over a datagram transport, it is increasingly being carried over TCP for larger responses commonly including DNSSEC responses and TLS or HTTPS for enhanced security. See below examples on how to use `dns-packet` to wrap DNS packets in these protocols: + +- [TCP](examples/tcp.js) +- [DNS over TLS](examples/tls.js) +- [DNS over HTTPS](examples/doh.js) + +## API + +#### `var buf = packets.encode(packet, [buf], [offset])` + +Encodes a DNS packet into a buffer containing a UDP payload. + +#### `var packet = packets.decode(buf, [offset])` + +Decode a DNS packet from a buffer containing a UDP payload. + +#### `var buf = packets.streamEncode(packet, [buf], [offset])` + +Encodes a DNS packet into a buffer containing a TCP payload. + +#### `var packet = packets.streamDecode(buf, [offset])` + +Decode a DNS packet from a buffer containing a TCP payload. + +#### `var len = packets.encodingLength(packet)` + +Returns how many bytes are needed to encode the DNS packet + +## Packets + +Packets look like this + +``` js +{ + type: 'query|response', + id: optionalIdNumber, + flags: optionalBitFlags, + questions: [...], + answers: [...], + additionals: [...], + authorities: [...] +} +``` + +The bit flags available are + +``` js +packet.RECURSION_DESIRED +packet.RECURSION_AVAILABLE +packet.TRUNCATED_RESPONSE +packet.AUTHORITATIVE_ANSWER +packet.AUTHENTIC_DATA +packet.CHECKING_DISABLED +``` + +To use more than one flag bitwise-or them together + +``` js +var flags = packet.RECURSION_DESIRED | packet.RECURSION_AVAILABLE +``` + +And to check for a flag use bitwise-and + +``` js +var isRecursive = message.flags & packet.RECURSION_DESIRED +``` + +A question looks like this + +``` js +{ + type: 'A', // or SRV, AAAA, etc + class: 'IN', // one of IN, CS, CH, HS, ANY. Default: IN + name: 'google.com' // which record are you looking for +} +``` + +And an answer, additional, or authority looks like this + +``` js +{ + type: 'A', // or SRV, AAAA, etc + class: 'IN', // one of IN, CS, CH, HS + name: 'google.com', // which name is this record for + ttl: optionalTimeToLiveInSeconds, + (record specific data, see below) +} +``` + +## Supported record types + +#### `A` + +``` js +{ + data: 'IPv4 address' // fx 127.0.0.1 +} +``` + +#### `AAAA` + +``` js +{ + data: 'IPv6 address' // fx fe80::1 +} +``` + +#### `CAA` + +``` js +{ + flags: 128, // octet + tag: 'issue|issuewild|iodef', + value: 'ca.example.net', + issuerCritical: false +} +``` + +#### `CNAME` + +``` js +{ + data: 'cname.to.another.record' +} +``` + +#### `DNAME` + +``` js +{ + data: 'dname.to.another.record' +} +``` + +#### `DNSKEY` + +``` js +{ + flags: 257, // 16 bits + algorithm: 1, // octet + key: Buffer +} +``` + +#### `DS` + +``` js +{ + keyTag: 12345, + algorithm: 8, + digestType: 1, + digest: Buffer +} +``` + +#### `HINFO` + +``` js +{ + data: { + cpu: 'cpu info', + os: 'os info' + } +} +``` + +#### `MX` + +``` js +{ + preference: 10, + exchange: 'mail.example.net' +} +``` + +#### `NS` + +``` js +{ + data: nameServer +} +``` + +#### `NSEC` + +``` js +{ + nextDomain: 'a.domain', + rrtypes: ['A', 'TXT', 'RRSIG'] +} +``` + +#### `NSEC3` + +``` js +{ + algorithm: 1, + flags: 0, + iterations: 2, + salt: Buffer, + nextDomain: Buffer, // Hashed per RFC5155 + rrtypes: ['A', 'TXT', 'RRSIG'] +} +``` + +#### `NULL` + +``` js +{ + data: Buffer('any binary data') +} +``` + +#### `OPT` + +[EDNS0](https://tools.ietf.org/html/rfc6891) options. + +``` js +{ + type: 'OPT', + name: '.', + udpPayloadSize: 4096, + flags: packet.DNSSEC_OK, + options: [{ + // pass in any code/data for generic EDNS0 options + code: 12, + data: Buffer.alloc(31) + }, { + // Several EDNS0 options have enhanced support + code: 'PADDING', + length: 31, + }, { + code: 'CLIENT_SUBNET', + family: 2, // 1 for IPv4, 2 for IPv6 + sourcePrefixLength: 64, // used to truncate IP address + scopePrefixLength: 0, + ip: 'fe80::', + }, { + code: 'TCP_KEEPALIVE', + timeout: 150 // increments of 100ms. This means 15s. + }, { + code: 'KEY_TAG', + tags: [1, 2, 3], + }] +} +``` + +The options `PADDING`, `CLIENT_SUBNET`, `TCP_KEEPALIVE` and `KEY_TAG` support enhanced de/encoding. See [optionscodes.js](https://github.com/mafintosh/dns-packet/blob/master/optioncodes.js) for all supported option codes. If the `data` property is present on a option, it takes precedence. On decoding, `data` will always be defined. + +#### `PTR` + +``` js +{ + data: 'points.to.another.record' +} +``` + +#### `RP` + +``` js +{ + mbox: 'admin.example.com', + txt: 'txt.example.com' +} +``` + +#### `RRSIG` + +``` js +{ + typeCovered: 'A', + algorithm: 8, + labels: 1, + originalTTL: 3600, + expiration: timestamp, + inception: timestamp, + keyTag: 12345, + signersName: 'a.name', + signature: Buffer +} +``` + +#### `SOA` + +``` js +{ + data: + { + mname: domainName, + rname: mailbox, + serial: zoneSerial, + refresh: refreshInterval, + retry: retryInterval, + expire: expireInterval, + minimum: minimumTTL + } +} +``` + +#### `SRV` + +``` js +{ + data: { + port: servicePort, + target: serviceHostName, + priority: optionalServicePriority, + weight: optionalServiceWeight + } +} +``` + +#### `TXT` + +``` js +{ + data: 'text' || Buffer || [ Buffer || 'text' ] +} +``` + +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. + +## License + +MIT |