1#!/bin/sh
2
3awk -f - $* <<EOF
4function bitcount(c) {
5	c=and(rshift(c, 1),0x55555555)+and(c,0x55555555)
6	c=and(rshift(c, 2),0x33333333)+and(c,0x33333333)
7	c=and(rshift(c, 4),0x0f0f0f0f)+and(c,0x0f0f0f0f)
8	c=and(rshift(c, 8),0x00ff00ff)+and(c,0x00ff00ff)
9	c=and(rshift(c,16),0x0000ffff)+and(c,0x0000ffff)
10	return c
11}
12
13function ip2int(ip) {
14	for (ret=0,n=split(ip,a,"\."),x=1;x<=n;x++) ret=or(lshift(ret,8),a[x])
15	return ret
16}
17
18function int2ip(ip,ret,x) {
19	ret=and(ip,255)
20	ip=rshift(ip,8)
21	for(;x<3;ret=and(ip,255)"."ret,ip=rshift(ip,8),x++);
22	return ret
23}
24
25function compl32(v) {
26	ret=xor(v, 0xffffffff)
27	return ret
28}
29
30BEGIN {
31	slpos=index(ARGV[1],"/")
32	if (slpos == 0) {
33		ipaddr=ip2int(ARGV[1])
34		dotpos=index(ARGV[2],".")
35		if (dotpos == 0)
36			netmask=compl32(2**(32-int(ARGV[2]))-1)
37		else
38			netmask=ip2int(ARGV[2])
39	} else {
40		ipaddr=ip2int(substr(ARGV[1],0,slpos-1))
41		netmask=compl32(2**(32-int(substr(ARGV[1],slpos+1)))-1)
42		ARGV[4]=ARGV[3]
43		ARGV[3]=ARGV[2]
44	}
45
46	network=and(ipaddr,netmask)
47	broadcast=or(network,compl32(netmask))
48
49	start=or(network,and(ip2int(ARGV[3]),compl32(netmask)))
50	limit=network+1
51	if (start<limit) start=limit
52
53	end=start+ARGV[4]
54	limit=or(network,compl32(netmask))-1
55	if (end>limit) end=limit
56
57	print "IP="int2ip(ipaddr)
58	print "NETMASK="int2ip(netmask)
59	print "BROADCAST="int2ip(broadcast)
60	print "NETWORK="int2ip(network)
61	print "PREFIX="32-bitcount(compl32(netmask))
62
63	# range calculations:
64	# ipcalc <ip> <netmask> <start> <num>
65
66	if (ARGC > 3) {
67		print "START="int2ip(start)
68		print "END="int2ip(end)
69	}
70}
71EOF
72