Leon M. Busch-George d7978e1f39 base-files: ipcalc.sh clarify range parameters in comment
To avoid confusion when working with ipcalc.sh, clarify that the last two
parameters belong to the range calculation and rename 'num' to the slightly
less ambiguous 'size'.

Signed-off-by: Leon M. Busch-George <leon@georgemail.eu>
2023-09-25 15:02:49 +02:00

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#!/usr/bin/awk -f
function bitcount(c) {
c=and(rshift(c, 1),0x55555555)+and(c,0x55555555)
c=and(rshift(c, 2),0x33333333)+and(c,0x33333333)
c=and(rshift(c, 4),0x0f0f0f0f)+and(c,0x0f0f0f0f)
c=and(rshift(c, 8),0x00ff00ff)+and(c,0x00ff00ff)
c=and(rshift(c,16),0x0000ffff)+and(c,0x0000ffff)
return c
}
function ip2int(ip) {
ret=0
n=split(ip,a,"\\.")
for (x=1;x<=n;x++)
ret=or(lshift(ret,8),a[x])
return ret
}
function int2ip(ip,ret,x) {
ret=and(ip,255)
ip=rshift(ip,8)
for(;x<3;x++) {
ret=and(ip,255)"."ret
ip=rshift(ip,8)
}
return ret
}
function compl32(v) {
ret=xor(v, 0xffffffff)
return ret
}
BEGIN {
slpos=index(ARGV[1],"/")
if (slpos == 0) {
ipaddr=ip2int(ARGV[1])
dotpos=index(ARGV[2],".")
if (dotpos == 0)
netmask=compl32(2**(32-int(ARGV[2]))-1)
else
netmask=ip2int(ARGV[2])
} else {
ipaddr=ip2int(substr(ARGV[1],0,slpos-1))
netmask=compl32(2**(32-int(substr(ARGV[1],slpos+1)))-1)
ARGV[4]=ARGV[3]
ARGV[3]=ARGV[2]
}
network=and(ipaddr,netmask)
prefix=32-bitcount(compl32(netmask))
print "IP="int2ip(ipaddr)
print "NETMASK="int2ip(netmask)
print "NETWORK="int2ip(network)
if (prefix<=30) {
broadcast=or(network,compl32(netmask))
print "BROADCAST="int2ip(broadcast)
}
print "PREFIX="prefix
# range calculations:
# ipcalc <ip> <netmask> <range_start> <range_size>
if (ARGC <= 3)
exit(0)
if (prefix<=30)
limit=network+1
else
limit=network
start=or(network,and(ip2int(ARGV[3]),compl32(netmask)))
if (start<limit) start=limit
if (start==ipaddr) start=ipaddr+1
if (prefix<=30)
limit=or(network,compl32(netmask))-1
else
limit=or(network,compl32(netmask))
end=start+ARGV[4]-1
if (end>limit) end=limit
if (end==ipaddr) end=ipaddr-1
if (start>end) {
print "network ("int2ip(network)"/"prefix") too small" > "/dev/stderr"
exit(1)
}
if (ipaddr > start && ipaddr < end) {
print "ipaddr inside range" > "/dev/stderr"
exit(1)
}
print "START="int2ip(start)
print "END="int2ip(end)
}