ip address networks in Python 3.3

Question

I am trying to convert a group of IP ranges that can start and end on any given address, but not necessarily on a .0, .127, or .255, etc. I have code that is mostly working; however, it can be slow for large ranges.

For example find_range("1.40.0.0","1.44.255.255") will take over a minute to return the correct result of 1.40.0.0/14 and 1.44.0.0/16.

Also, I am have trouble when the starting range does not end with a .0. How can I fix these 2 issues: slowness on large IP ranges and when the starting range does not end in .0?

For the slowness problem, I tried skipping more than 1 address at a time, but then this would miss smaller ranges.

import ipaddress, socket, struct
def ip2int(addr): 
 return struct.unpack("!I", socket.inet_aton(addr))[0] 
def int2ip(addr): 
 return socket.inet_ntoa(struct.pack("!I", addr)) 
def ipminus(ip, amount=1):
 tmp = ip2int(ip)
 return int2ip(tmp - amount)
def ipplus(ip):
 tmp = ip2int(ip)
 return int2ip(tmp + 1)
def cidr_notation(a,b):
 for mask in range(32, 6, -1):
 test = "%s/%s" % (a,mask)
 try:
 n = ipaddress.IPv4Network(test,False)
 if b == "%s" % (n.broadcast_address):
 return test
 except:
 pass
 return None
def split_range(a,b):
 a1 = ip2int(a)
 b1 = ip2int(b)
 needed = 1
 while needed:
 result = cidr_notation(a,b)
 if result:
 print( "* %16s\t%16s\t%16s" % (result, a, b))
 if ip2int(b) > b1:
 needed = 0
 else:
 a = ipplus(b)
 b = int2ip(b1)
 else:
 b = ipminus(b)
 return result
def find_range(x,y):
 result = cidr_notation(x,y)
 if result:
 print( "# %16s\t%16s\t%16s" % (result, x, y))
 else:
 split_range(x,y)
# main...
print("%16s\t%16s\t%16s" % ("mask","start","end"))
print("%16s\t%16s\t%16s" % ("----","-----","---"))
find_range("128.191.0.0","128.191.255.255") #fast
find_range("10.55.96.106","10.55.96.106") #fast
find_range("5.135.14.0","5.135.61.11") #slow
find_range("4.31.64.72","4.59.175.255") #does not work, how to fix?
find_range("1.40.0.0","1.44.255.255") #very slow
# 5000 more find_range() calls...

• Jon Chen: Have you tried looking at this existing code from ipaddress.py? code.google.com/p/ipaddress-py/source/browse/ipaddress.py#248

Answer 1

Based on bsdlp's comment, this code got a lot simpler and faster!

 def find_range(x,y,c_code="",c_name=""):
 print()
 print("%29s\t%23s" % (x,y))
 print("%16s\t%16s\t%16s\t%4s\t%s" % ("mask","start","end","code","name"))
 print("%16s\t%16s\t%16s\t%4s\t%s" % ("----","-----","---","----","----"))
 result = ipaddress.summarize_address_range( ipaddress.IPv4Address(x), ipaddress.IPv4Address(y) )
 for entry in result:
 net = str( entry.network_address )
 bcast = str( entry.broadcast_address )
 print( "%16s\t%16s\t%16s\t%4s\t%s" % (entry, net, bcast,c_code,c_name))