How to get each IP address in subnet?

Question

So the code below was posted by another user a while back.

I'm wondering what the best way to get each IP address between "net['firstip'] and net['lastip']" is?

I tried converting from decimal to binary a few ways, but it wasn't working. My thought was to for() increase the binary firstip until it reaches the lastip , and convert each step to a decimal equivalent to put in a new array.

All help is appreciated. I put *** by the two specific pieces I'm trying to find the IP's between.

function zerofill($val,$len,$reverse = false){
    while(strlen($val)<$len)
        if($reverse)
            $val .= "0";
        else
            $val = "0".$val;
    return $val;

}


function hextoip($hex){
    for($i=0;$i<4;$i++)
        @$ip .= base_convert(substr($hex,$i*2,2),16,10).".";
    $ip = substr($ip,0,-1);
    return $ip;
}



function iptohex($ip){
    $iparr = explode(".",$ip);
    foreach($iparr as $i => $group){
        @$hex .= zerofill(base_convert($group,10,16),2);
    }
    return $hex;
}



function hextobin($hex){
    $bin = zerofill(base_convert($hex,16,2),32);
    return $bin;
}



function bintohex($bin) {
    $hex = zerofill(base_convert($bin,2,16),8);
    return $hex;
}



function getnet($ip, $netmask){
    $iphex = iptohex($ip);
    $netbin = hextobin($iphex);
    $maskhex = iptohex($netmask);
    $maskbin = hextobin($maskhex);

    $hostbits = substr($maskbin,strpos($maskbin,"0"));
    $netbits = substr($maskbin,0,strpos($maskbin,"0"));
    $nethex = bintohex(zerofill(substr($netbin,0,strlen($netbits)),32,true));

    $hosts = pow(2,strlen($hostbits));
    $available_hosts = $hosts-3;

    $net["ip"] = $ip;
    $net["mask"] = $netmask;
    $net["network"] = hextoip($nethex);
    $net["netstr"] = $net["network"]."/".strlen($netbits);  
    $net["hosts"] = $available_hosts;
    *** $net["firstip"] = hextoip(zerofill(base_convert(base_convert($nethex,16,10)+1,10,16),8));;
    *** $net["lastip"] = hextoip(zerofill(base_convert(base_convert($nethex,16,10)+$available_hosts+1,10,16),8));
    $net["broadcast"] = hextoip(zerofill(base_convert(base_convert($nethex,16,10)+$available_hosts+2,10,16),8));
    return $net;
} `

Answer 1

You can use the following code to get all IPs from the first to last IP:

<?php

function getIpRange(  $cidr) {

    list($ip, $mask) = explode('/', $cidr);

    $maskBinStr =str_repeat("1", $mask ) . str_repeat("0", 32-$mask );      //net mask binary string
    $inverseMaskBinStr = str_repeat("0", $mask ) . str_repeat("1",  32-$mask ); //inverse mask

    $ipLong = ip2long( $ip );
    $ipMaskLong = bindec( $maskBinStr );
    $inverseIpMaskLong = bindec( $inverseMaskBinStr );
    $netWork = $ipLong & $ipMaskLong; 

    $start = $netWork+1;//ignore network ID(eg: 192.168.1.0)

    $end = ($netWork | $inverseIpMaskLong) -1 ; //ignore brocast IP(eg: 192.168.1.255)
    return array('firstIP' => $start, 'lastIP' => $end );
}

function getEachIpInRange ( $cidr) {
    $ips = array();
    $range = getIpRange($cidr);
    for ($ip = $range['firstIP']; $ip <= $range['lastIP']; $ip++) {
        $ips[] = long2ip($ip);
    }
    return $ips;
}

$cidr = '172.16.0.0/27'; // max. 30 ips
print_r(getEachIpInRange ( $cidr));

/* output: 
Array                                                                 
(                                                                     
    [0] => 172.16.0.1                                                 
    [1] => 172.16.0.2
    [2] => 172.16.0.3
    ...
    [27] => 172.16.0.28                                               
    [28] => 172.16.0.29                                               
    [29] => 172.16.0.30
) 
*/

If you need more infos have a look into the PHP manual right here: http://php.net/manual/de/function.ip2long.php
Some parts from my example code are from this manual.