convert Ipv4 and IpV6 to netmask

[edotom]

Hi

I want to convert ipv4 and Ipv6 addresses to netmask lenght like:

255.255.0.0  

result 

16

 

I was thinking in splitting into arrays and find the byte and then just count the number of bits

It this possible?

 

thanks in advance

[requinix]

strspn(base_convert(bin2hex(inet_pton("255.255.0.0")), 16, 2), "1")

I'm sure there's a better solution.

[edotom]

It works !! but just for ipv4,  How can I convert Ipv6 to bin?  

[requinix]

It should work for IPv6 too. Maybe your PHP doesn't support it?

var_dump(defined('AF_INET6')); // true=has support, false=no support

What do you get when you try? Would be a warning and a result of 0.

[edotom]

sadly I receive false, therefore there's no support for 64

[requinix]

Then you'll probably have to make your own function to deal with it. Since the problem is simply finding the number of leading 1 bits I'd just go with a function to do both IPv4 and IPv6 that gives you exactly the result you need. Means you don't have to parse the address for real, simply count how many 1 bits you find until the first 0.

"Simply". Thing is that there are a few valid formats you'd have to account for: pieces not having all four hex digits, omitted zeroes with a ::, a trailing IPv4 address... Unless you can restrict the input.