packet-socket

packet-socket

Node.js package implementing socket for receiving OSI layer 2 packets

API

Assume that packet-socket module is required in following examples.

var packet = require('packet-socket')

Opening socket

var socket = packet.openSocket({device: 'lo'})

openSocket call accepts options object as argument. Option device should contain interface name on which open raw packet socket.

Closing socket

socket.close()

Few words about address

Some functions require address as an argument. Formats accepted:

• String 'aa:bb:cc:11:22:33'
• Array [0xaa, 0xbb, 0xcc, 0x11, 0x22, 0x33]
• Buffer new Buffer([0xaa, 0xbb, 0xcc, 0x11, 0x22, 0x33])

Joining and leaving Multicast Membership

socket.joinMC(packet.PROMISCIOUS)
socket.joinMC(packet.ALL_MULTICAST)
socket.joinMC('11:00:de:ad:be:ef')

socket.leaveMC(packet.PROMISCIOUS)
socket.leaveMC(packet.ALL_MULTICAST)
socket.leaveMC('11:00:de:ad:be:ef')

joinMC or leaveMC method accepts as argument either multicast address or integer constant:

• PROMISCIOUS - sets interface to PROMISCIOUS mode, catching all packets
• ALL_MULTICAST - catch all multicast messages

Sending

packet.send(new Buffer('message to send'), '58:00:00:00:00:01', function(err, bytes) {

})

Callback function argument will provide information if send failed, then err will contain information, if it is null, then bytes will contain number of bytes transferred.

Events

Socket returned by openSocket can emit events:

• message - this event is emited when packet is received, it contain buffer with message received, source and destination addresses (in string format)

packet.on('message', function(message, source, destination) {
});

• error - this event is emited in case of any error, it contain error object

packet.on('error', function(error) {});

Packet socket root reqirement

Opening packet (man 7 packet) socket requires root permission or cap_net_raw capability

Testing

Module contains unit test, which can be invoked by command

npm test

This however requires build suite ready, with CppUTest libraries installed.