socket-cleanup.py

#!/usr/bin/python
import os
import subprocess
from gi.repository import GLib, NMClient

def active_connections_changed(*args):
    for sock in os.listdir(os.path.expanduser('~/.ssh/sockets')):
        user, hostport = sock.split('@')
        host, port = hostport.split(':')
        subprocess.call(['ssh', '-O', 'stop', '-l', user, '-p', port, host])

c = NMClient.Client.new()
c.connect('notify::active-connections', active_connections_changed)
GLib.MainLoop().run()