#!/usr/bin/python
import sys, re
from netaddr import IPAddress

if len(sys.argv) != 2:
	print >>sys.stderr, "Usage: %s filename" % sys.argv[0]
	sys.exit(1)

log = open(sys.argv[1], "a")

# group 1 must be the prefix, group 2 the IP, group 3 the suffix
ipmatch = r"([0-9a-f.:]+)"
accesslog = re.compile(r"^(\S+ )"+ipmatch+r"( .*)$")
errorlog = re.compile(r"^(.* \[client )"+ipmatch+r"(\] .*)$")

while True:
	line = sys.stdin.readline()
	if not line: break
	# process this line
	match = accesslog.search(line)
	if match is None:
		match = errorlog.search(line)
	# check what we got
	if match is None:
		# unknown line
		log.write(line)
	else:
		prefix = match.group(1)
		ip = match.group(2)
		suffix = match.group(3)
		try:
			ip = IPAddress(ip) # parse the addres
			ip = ip & (IPAddress('255.255.255.0') if ip.version == 4 else IPAddress('ffff:ffff:ffff::')) # mask out a bunch of bits
			# now we have a parsed representation of the IP address we want to print
			log.write(prefix+str(ip)+suffix+"\n")
		except (ValueError, netaddr.core.AddrFormatError):
			# not actually an IP address...
			log.write(line)
	log.flush()