wiccasoft / stun

Session Traversal Utilities for NAT (STUN) server

stun

Session Traversal Utilities for NAT (STUN) server. Implements RFC5389.

Install

npm i stun

Usage

const stun = require('stun')

const { STUN_BINDING_REQUEST, STUN_ATTR_XOR_MAPPED_ADDRESS } = stun.constants

const server = stun.createServer()
const request = stun.createMessage(STUN_BINDING_REQUEST)

server.once('bindingResponse', stunMsg => {
  console.log('your ip:', stunMsg.getAttribute(STUN_ATTR_XOR_MAPPED_ADDRESS).value.address)

  server.close()
})

server.send(request, 19302, 'stun.l.google.com')

API

createMessage(type): StunMessage

Creates an StunMessage object of the specified type with random transaction field. The type argument is a number that should be a message type. See constants below.

createServer([socket: dgram.Socket]): StunServer

Creates a StunServer object. An optional socket argument should be instance of dgram.Socket. If socket is not specifed, the dgram.Socket will be created with udp4 type and will bound to the "all interfaces" address on a random port.

validateFingerprint(message: StunMessage): bool

Check a FINGERPRINT attribute if it is specifed.

validateMessageIntegrity(message: StunMessage, key: string): bool

Check a MESSAGE_INTEGRITY attribute if it is specifed.

stunServer.on('bindingResponse', (stunMsg) => {
  if (!stun.validateFingerprint(stunMsg)) {
    // do stuff...
  }

  if (!stun.validateMessageIntegrity(stunMsg, icePassword)) {
    // do stuff...
  }
})

class StunMessage

The StunMessage class is an utility that encapsulates the STUN protocol.

Instances of the StunMessage class can be created using the stun.createMessage() function or the StunMessage.from method.

• static from(message: Buffer): StunMessage

Creates a StunMessage object from a message Buffer.

• get type
• get transactionId

Returns the type and transactionId fields from the current message.

• setType(type)

Set the type of the message. The type argument is a number that should be a message type. See constants below.

• setTransactionID(transaction: Buffer): bool

Set the transaction id of the message. The transaction argument should be a Buffer and have length 12 bytes.

• isLegacy(): bool

Returns true if the message confirms to RFC3489 rather than RFC5389.

• addAttribute(type, address: string, port: number)

Adds a type attribute to the current message. The type argument should be one of STUN_ATTR_MAPPED_ADDRESS, STUN_ATTR_ALTERNATE_SERVER, STUN_ATTR_XOR_MAPPED_ADDRESS.

stunMsg.addAttribute(STUN_ATTR_XOR_MAPPED_ADDRESS, '8.8.8.8', 19302)

• addAttribute(type, value: String|Buffer[, encoding: string = 'utf8'])

Adds a type attribute to the current message. The type argument should be one of STUN_ATTR_USERNAME, STUN_ATTR_REALM, STUN_ATTR_NONCE, STUN_ATTR_SOFTWARE, STUN_ATTR_ORIGIN, STUN_ATTR_USE_CANDIDATE, STUN_ATTR_ICE_CONTROLLED, STUN_ATTR_ICE_CONTROLLING.

stunMsg.addAttribute(STUN_ATTR_SOFTWARE, 'node/8.2.0 stun/1.0.0')

• addAttribute(type, value: number)

Adds a type attribute to the current message. The type argument should be one of STUN_ATTR_RETRANSMIT_COUNT, STUN_ATTR_PRIORITY, STUN_ATTR_NETWORK_INFO, STUN_ATTR_NOMINATION.

stunMsg.addAttribute(STUN_ATTR_PRIORITY, 123)

• addAttribute(type, value: array<number>)

Adds a type attribute to the current message. The type argument should be STUN_ATTR_UNKNOWN_ATTRIBUTES.

stunMsg.addAttribute(STUN_ATTR_UNKNOWN_ATTRIBUTES, [2, 3, 4])

• addAttribute(type, code: number, reason: string)

Adds a type attribute to the current message. The type argument should be STUN_ATTR_ERROR_CODE.

stunMsg.addAttribute(STUN_ATTR_ERROR_CODE, STUN_CODE_UNAUTHORIZED, STUN_REASON_UNAUTHORIZED)

• getAttribute(type): StunAttribute

Returns the StunAttribute attribute of the specified type. The type argument is a number that should be an attribute type. See constants below.

• removeAttribute(type): bool

Remove a type attribute from the current message. Returns true if an attribute was removed. The type argument is a number that should be an attribute type. See constants below.

• addMessageIntegrity(key: string)

Adds a MESSAGE-INTEGRITY attribute that is valid for the current message. The key is the HMAC key used to generate the cryptographic HMAC hash.

• addFingerprint()

Adds a FINGERPRINT attribute that is valid for the current message.

• toBuffer(): Buffer

Converts a StunMessage object to the buffer.

class StunServer

The StunServer class is an EventEmitter that encapsulates a STUN server.

• new StunServer(socket: dgram.Socket)

Creates a new StunServer object. The socket argument should be an instance of dgram.Socket. The incoming message is silently ignored when it is not a stun one.

• send(message: StunMessage, port: number, address: string[, cb: function])

Sends the StunMessage message on the socket. The destination port and address must be specified. An optional callback function will be called when the message has been sent.

• close()

Stops the processing of the incoming messages and emits close event.

• Event: bindingRequest

Emitted when the STUN_BINDING_REQUEST message is available on a socket.

• Event: bindingIndication

Emitted when the STUN_BINDING_INDICATION message is available on a socket.

• Event: bindingResponse

Emitted when the STUN_BINDING_RESPONSE message is available on a socket.

• Event: bindingError

Emitted when the STUN_BINDING_ERROR_RESPONSE message is available on a socket.

• Event: close

Emitted when the server closes.

class StunAttribute

The StunAttribute class is an utility for adding an attributes to the StunMessage message.

• get type

Returns the attribute type. See constants below.

• get value

Returns the value of the attribute. It depends on the value type of the attribute.

stunMsg.getAttribute(STUN_ATTR_USERNAME).value        // string
stunMsg.getAttribute(STUN_ATTR_PRIORITY).value        // number
stunMsg.getAttribute(STUN_ATTR_MAPPED_ADDRESS).value  // object

constants: object

These are the types of STUN messages defined in RFC 5389:

• STUN_BINDING_REQUEST
• STUN_BINDING_INDICATION
• STUN_BINDING_RESPONSE
• STUN_BINDING_ERROR_RESPONSE

Thsese are all known STUN attributes, defined in RFC 5389 and elsewhere:

• STUN_ATTR_MAPPED_ADDRESS
• STUN_ATTR_USERNAME
• STUN_ATTR_MESSAGE_INTEGRITY
• STUN_ATTR_ERROR_CODE
• STUN_ATTR_UNKNOWN_ATTRIBUTES
• STUN_ATTR_REALM
• STUN_ATTR_NONCE
• STUN_ATTR_XOR_MAPPED_ADDRESS
• STUN_ATTR_SOFTWARE
• STUN_ATTR_ALTERNATE_SERVER
• STUN_ATTR_FINGERPRINT
• STUN_ATTR_ORIGIN
• STUN_ATTR_RETRANSMIT_COUNT
• STUN_ATTR_PRIORITY
• STUN_ATTR_USE_CANDIDATE
• STUN_ATTR_ICE_CONTROLLED
• STUN_ATTR_ICE_CONTROLLING
• STUN_ATTR_NOMINATION
• STUN_ATTR_NETWORK_INFO

These are the types of STUN error codes defined in RFC 5389 and 5245:

• STUN_CODE_TRY_ALTERNATE
• STUN_CODE_BAD_REQUEST
• STUN_CODE_UNAUTHORIZED
• STUN_CODE_UNKNOWN_ATTRIBUTE
• STUN_CODE_STALE_CREDENTIALS
• STUN_CODE_STALE_NONCE
• STUN_CODE_SERVER_ERROR
• STUN_CODE_GLOBAL_FAILURE
• STUN_CODE_ROLE_CONFLICT

These are the strings for the error codes above:

• STUN_REASON_TRY_ALTERNATE
• STUN_REASON_BAD_REQUEST
• STUN_REASON_UNAUTHORIZED
• STUN_REASON_UNKNOWN_ATTRIBUTE
• STUN_REASON_STALE_CREDENTIALS
• STUN_REASON_STALE_NONCE
• STUN_REASON_SERVER_ERROR
• STUN_REASON_ROLE_CONFLICT

License

MIT, 2017 (c) Dmitriy Tsvettsikh