Monitor network usage with SNMP

network-traffic.js

var exec = require('child_process').exec

function howManyOctets(cb) {
	child = exec('snmpwalk -v 2c -c admin 192.168.0.1 IF-MIB::ifHCInOctets.1', // change to .32 to measure external usage
		function (error, stdout, stderr) {
			var numOctets = 0
			stdout.split('\n').forEach(function (line) {
				numOctets += parseInt(/: (\d+)/.exec(stdout)[1])
			})
			cb(numOctets)
		}
	)
}

var lastOctets
var lastTime
function main() {
	howManyOctets(function (octets) {
		var now = Date.now()
		if (!lastOctets) {
			lastOctets = octets
			lastTime = now
			return main()
		} else {
			var diff = octets - lastOctets
			var dt = now - lastTime
			lastTime = now
			console.log((diff/dt).toFixed(1),"kB/s")
			lastOctets = octets
			setTimeout(main, 1000)
		}
	})
}
main()