OpenSSL DTLS1.2 Bindings

This module enables your application to listen for incoming DTLS1.2 connections.
It uses OpenSSL 1.1.1, which is shipped with Node.js version 10 up to version 16.

API

``js
const DTLS = require('openssl-dtls');
const srv = DTLS.createServer(opts);
`

Spawns a new server. opts is an object:
key: Buffer. The server's private key in PEM format. Mandatory.*
cert: Buffer. The server's certificate in PEM format. Mandatory.*
ca: Buffer. CA certificate for validation of client certificates. Optional.*
requestCert: Boolean. Request certificate from client. Default: false.*
rejectUnauthorized: Boolean. Reject invalid client certificates. Default: false.*
mtu: Number. The wire's MTU. Default: 1500 Ethernet MTU - 40 IPv6 Header - 8 UDP Header = 1452.*
ciphers: String. Allowed ciphers. Further details: OpenSSL Cipher List Format. Optional.*
* socket: Instances of dgram.Socket. By default a new 'udp6' dgram socket will be created.
handshakeTimeout: Duration in milliseconds how long a DTLS handshake can take until it will be aborted and the state is removed. Default: 30 1000ms
connectionTimeout: Duration in milliseconds how long a DTLS connection can stay established without any received data until the connection is closed. Default: 10 60 1000ms*
* retransmitTimeout: Number or Function. A number states the initial retransmit timeout in microseconds that is doubled in every iteration. Function: (lastTimeout) => nextTimeout, where lastTimeout is zero in the first iteration. Default: 1000000.

$3

#### Method: bind()

`js
srv.bind(...);
`

Proxy method for the bind() method of the socket specified with DTLS.createServer(). If you haven't specified anything, have a look into the documentation of UDP/Datagram.

#### Method: close()

`js
srv.close([cb]);
`

Shuts down the server and calls cb once the underlying socket has been closed.

#### Event: connection

`js
srv.on('connection', (info) => {...});
`

Is raised if a client has started a handshake. info:
* address: Remote address.
* port: Remote port.

#### Event: error

`js
srv.on('error', (err, info) => {...});
`

Is raised if something went wrong. err is an instance of Error. info:
* address: Remote address.
* port: Remote port.

#### Event: secureConnection

`js
srv.on('secureConnection', (peer) => {...});
`

Is raised once a handshake has been successfully finished. peer is an instance of Peer.

$3

#### Method: address()

`js
const info = peer.address();
`

Returns the peers address. info:
* address: Remote address.
* port: Remote port.

#### Method: getCertChain()

`js
const chain = peer.getCertChain();
`

Returns the peers certificate chain. chain is a Buffer containing the certificates in PEM format. If no certificates has been prensented by the client, chain is and empty Buffer.

#### Method: send()

`js
peer.send(message);
`

Sends message to the client. message has to be a Buffer.

#### Method: end()

`js
peer.end();
`

Closes connection to peer.

#### Event: message

`js
peer.on('message', (message) => {...});
`

Is raised if a message has been received from peer.


#### Event: close

`js
peer.on('close', () => {...});
`

Is raised if the connection to peer` has been closed.