I have an IP like this: 12.12.12.12
I'm looping through different IP ranges (in 12.12.12.0/24 (example)) format, and trying to see if the IP is in the range.
I have tried various methods such as inet_addr and comparing but I can't seem to get it.
Is there an easy way to do this? I'm using Windows.
Just test whether:
(ip & netmask) == (range & netmask)
You can determine the netmask from the CIDR parameters range/netbits
as follows:
uint32_t netmask = ~(~uint32_t(0) >> netbits);
Take the binary representation and zero out what is not matching your network mask.
Clarification: Let's say you have the IP abcd
and want to match it to efgh/i
then, you can throw the IP into one unsigned integer, uint32_t ip = a<<24 + b<<16 + c<<8 + d
and do the same with uint32_t range = e<<24 + f<<16 + g<<8 + h
. Now you can use your network mask: uint32_t mask = (~0u) << (32-i)
. Now, you can simply check if ip
"is in" range
by comparing them: ip & mask == range & mask
.
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