network-simulator

simulate a low-level computer network

one-way example

This network forwards connections along a one-way linear path:

var sim = require('network-simulator')()
 
for (var i = 0; i < 20; i++) (function (i) {
  var node = sim.createNode(i, [ 'eth0', 'eth1' ])
  node.on('eth0:message', function (buf) {
    node.send('eth1', buf)
  })
})(i)
 
for (var i = 1; i < 20; i++) {
  sim.link((i-1) + ':eth1', i + ':eth0')
}
 
sim.nodes[19].on('eth1:message', function (buf) {
  console.log('MESSAGE: ' + buf)
})
sim.nodes[4].send('eth1', Buffer('hello!'))

ip example

This network sends IP messages for simple routing across a linear chain:

var sim = require('network-simulator')()
var ip = require('ip-packet')
 
for (var i = 1; i <= 20; i++) (function (i) {
  var node = sim.createNode(i, [ 'eth0', 'eth1' ])
  node.on('eth0:message', onmessage(false, 'eth1'))
  node.on('eth1:message', onmessage('eth0', false))
  function onmessage (lt, gt) {
    return function (buf) {
      var packet = ip.decode(buf)
      var octets = packet.destinationIp.split('.')
      if (packet.destinationIp === '192.168.1.' + i) {
        node.emit('packet', packet)
      } else if (lt && i > octets[3]) {
        node.send(lt, buf)
      } else if (gt && i < octets[3]) {
        node.send(gt, buf)
      }
    }
  }
})(i)
 
for (var i = 1; i < 20; i++) {
  sim.link(i + ':eth1', (i+1) + ':eth0')
}
 
sim.nodes[3].on('packet', function (packet) {
  console.log(packet)
})
sim.nodes[16].send('eth0', ip.encode({
  version: 4,
  protocol: 0,
  sourceIp: '192.168.1.16',
  destinationIp: '192.168.1.3',
  data: Buffer('hello')
}))

api

var Simulator = require('network-simulator')

var sim = Simulator()

Create a new simulator instance sim.

var node = sim.createNode(key, ifaces)

Create a network node identified by a string key and an array of string interface names ifaces.

sim.nodes

Look up a previously created node by its key.

sim.link(a, b)

Wire the network interfaces for a and b together.

a and b should be strings with a colon separator: key:iface.

node.send(iface, buf)

Send buf out iface. A 'message' event is sent to any linked interfaces.

node.link(iface, target, targetIface)

Wire targetIface on target (a node instance) to the local iface.

node.on('IFACE:message', function (buf) {})

When data is sent to IFACE, this event fires.

install

npm install network-simulator

license

MIT