ifco.py

# Usage: ifconfig | python ifco.py
import sys
import socket
readline = sys.stdin.readline

def ip2num(a):
    return int(socket.inet_aton(a).encode('hex'), 16)

def num2ip(i):
    return socket.inet_ntoa(hex(i)[2:].decode('hex'))

while True:
    while True:
        line = readline()
        if 'Link encap:Ethernet' in line:
            break
        if not line:
            break
    if not line:
        break
    if not line.startswith('eth0.'):
        continue

    num = int(line.split()[0][5:])

    while True:
        line = readline()
        if 'inet addr:' in line:
            break

    inetl = line.split()
    s_addr = inetl[1].split(':')[1]
    s_bcast = inetl[3].split(':')[1]
    addr = ip2num(s_addr)
    bcast = ip2num(s_bcast)
    print 'h3. VLAN %d %s/%d' % (num, num2ip(addr & bcast), bin(bcast).count('1'))