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December 4, 2018 06:15
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Get the start and end IP from an IP Range by a CIDR (Classless Inter-Domain Routing) notation, complete or incomplete. As discussed here: https://blog.gerbenjacobs.nl/get-ip-range-by-cidr-notation.html
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<?php | |
function getIPRangeByCIDR($cidr) { | |
// Making sure IPs are valid | |
$ipdata = explode('/', ltrim($cidr, '0')); | |
$dotcount = substr_count($ipdata[0], '.'); | |
if ($dotcount != 3) { | |
$ipdata[0] .= str_repeat('.0', (3-$dotcount)); | |
} | |
$cidr_address = sprintf('%s/%s', $ipdata[0], $ipdata[1]); | |
// By 'unknown' http://www.php.net/manual/en/ref.network.php#30910 | |
$first = substr($cidr_address, 0, strpos($cidr_address, "/")); | |
$netmask = substr(strstr($cidr_address, "/"), 1); | |
$first_bin = str_pad(decbin(ip2long($first)), 32, "0", STR_PAD_LEFT); | |
$last_bin = ''; | |
$netmask_bin = str_pad(str_repeat("1", (integer)$netmask), 32, "0", STR_PAD_RIGHT); | |
for ($i = 0; $i < 32; $i++) { | |
if ($netmask_bin[$i] == "1") | |
$last_bin .= $first_bin[$i]; | |
else | |
$last_bin .= "1"; | |
} | |
$last = long2ip(bindec($last_bin)); | |
return array($first, $last); | |
} | |
print_r(getIPRangeByCIDR('190.151.192/18')); | |
// Array ( [0] => 190.151.192.0 [1] => 190.151.255.255 ) | |
print_r(getIPRangeByCIDR('17/8')); | |
// (Apple) Array ( [0] => 17.0.0.0 [1] => 17.255.255.255 ) | |
print_r(getIPRangeByCIDR('65.192/11')); | |
// (NSA?) Array ( [0] => 65.192.0.0 [1] => 65.223.255.255 ) | |
?> |
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