Count IPv4 vs IPv6 traffic flowing over a Linux bridge

ip-family-traffic-counter.py

#!/usr/bin/python3
#
# I have a Linux machine between my ISP's router and my switch. Two interfaces
# are bridged so I can inspect all traffic coming in and going out.
#
#
# bridge name	bridge id		STP enabled	interfaces
# br1		8000.8eb20d8d9b94	no		      enp0s20f0
#  							                      enp0s20f1
#
#
# iptables -I FORWARD -i br1 -o br1 -j ACCEPT
# ip6tables -I FORWARD -i br1 -o br1 -j ACCEPT
#
# Using this information I can create graphs of my IPv4 vs IPv6 traffic
#
# A systemd timer runs executes this script every 10 seconds
#
# Author: Wido den Hollander <wido@denhollander.io>
#
from subprocess import check_output, CalledProcessError
import datetime
from influxdb import InfluxDBClient

INFLUX_HOST = 'influxdb'
INFLUX_DB = 'traffic'


def execute(cmd):
    return check_output(cmd, shell=True).decode()


def get_ip_stats():
    stats = {'ipv4': {}, 'ipv6': {}}

    ipv4 = execute('iptables -L -Z -v -x -n --line-numbers|grep ^1|grep br1').split()
    ipv6 = execute('ip6tables -L -Z -v -x -n --line-numbers|grep ^1|grep br1').split()

    stats['ipv4']['packets'] = int(ipv4[1])
    stats['ipv4']['bytes'] = int(ipv4[2])

    stats['ipv6']['packets'] = int(ipv6[1])
    stats['ipv6']['bytes'] = int(ipv6[2])

    return stats


stats = get_ip_stats()

now = datetime.datetime.utcnow().replace(tzinfo=datetime.timezone.utc).isoformat()

measurements = [
    {
        'measurement': 'ip_traffic',
        'time': now,
        'fields': {
            'packets': stats['ipv4']['packets'],
            'bytes': stats['ipv4']['bytes'],
        },
        'tags': {
            'family': 4
        }
    },
    {
        'measurement': 'ip_traffic',
        'time': now,
        'fields': {
            'packets': stats['ipv6']['packets'],
            'bytes': stats['ipv6']['bytes']
        },
        'tags': {
            'family': 6
        }
    }
]

client = InfluxDBClient(host=INFLUX_HOST, database=INFLUX_DB)

client.write_points(measurements)