I'm trying to perform some basic mathematics on IP Addresses. IP's are
normally represented as 32 bit unsigned integers. However I am getting
strange results when using the operators in PHP.

If you run this is a mysql query browser: select (3388826209 &
4294867288) as val; it will tell you the correct answer is:
3388760128. This is the answer I want. My snippet of PHP code is here:

$ip = $networkObjectRow['sipv4addr'];
$subnet = $networkObjectRow['eipv4addr'];

//make php treats these likes numbers and not strings

$ip += (int)0;
$subnet += (int)0;

if ($ip == 0)
return "NOT SET";

$ans = $ip & $subnet; //Bitwise AND.

print("<!-- sip F (ip=$ip,subnet=$subnet) returned is
$ans -->\n");
return ($ans);

However my output is like this:

<!-- sip F (ip=170419457,subnet=4294967040) returned is 170419456 -->
<!-- sip F (ip=170419457,subnet=4294967040) returned is 170419456 -->
<!-- sip F (ip=3388826225,subnet=4294967280) returned is -906141072 --
>
<!-- sip F (ip=3388826225,subnet=4294967280) returned is -906141072 --
>
<!-- sip F (ip=170419969,subnet=4294967040) returned is 170419968 -->

<!-- sip F (ip=170419969,subnet=4294967040) returned is 170419968 -->

Where the IP starts 17... the answer is correct. When the value starts
3388 the value is wrong.

I guess this is because PHP is treating the number as a 64 bit one
rather than an unsigned 32 bit one but I'm not really sure. Can anyone
please?

On Mar 28, 11:15 am, Philluminati <Phillip.Ross.Tay...@gmail.com>
wrote:
> I'm trying to perform some basic mathematics on IP Addresses. IP's are
> normally represented as 32 bit unsigned integers. However I am getting
> strange results when using the operators in PHP.
>
> If you run this is a mysql query browser: select (3388826209 &
> 4294867288) as val; it will tell you the correct answer is:
> 3388760128. This is the answer I want. My snippet of PHP code is here:
>
> $ip = $networkObjectRow['sipv4addr'];
> $subnet = $networkObjectRow['eipv4addr'];
>
> //make php treats these likes numbers and not strings
>
> $ip += (int)0;
> $subnet += (int)0;
>
> if ($ip == 0)
> return "NOT SET";
>
> $ans = $ip & $subnet; //Bitwise AND.
>
> print("<!-- sip F (ip=$ip,subnet=$subnet) returned is
> $ans -->\n");
> return ($ans);
>
> However my output is like this:
>
> <!-- sip F (ip=170419457,subnet=4294967040) returned is 170419456 -->
> <!-- sip F (ip=170419457,subnet=4294967040) returned is 170419456 -->
> <!-- sip F (ip=3388826225,subnet=4294967280) returned is -906141072 --
>
> <!-- sip F (ip=3388826225,subnet=4294967280) returned is -906141072 --
>
> <!-- sip F (ip=170419969,subnet=4294967040) returned is 170419968 -->
>
> <!-- sip F (ip=170419969,subnet=4294967040) returned is 170419968 -->
>
> Where the IP starts 17... the answer is correct. When the value starts
> 3388 the value is wrong.
>
> I guess this is because PHP is treating the number as a 64 bit one
> rather than an unsigned 32 bit one but I'm not really sure. Can anyone
> please?

My current very-hacky workaround is to do this:

$res = mysql_query("SELECT $ip & $subnet;");

....

but as you can see it's bordering on "very wrong"!

Philluminati wrote:
>
> $ip = $networkObjectRow['sipv4addr'];
> $subnet = $networkObjectRow['eipv4addr'];
>
> //make php treats these likes numbers and not strings
>
> $ip += (int)0;
> $subnet += (int)0;

$ip = (int)$networkObjectRow['sipv4addr'];
$subnet = (int)$networkObjectRow['eipv4addr'];


>
> print("<!-- sip F (ip=$ip,subnet=$subnet) returned is
> $ans -->\n");
> return ($ans);
>
> However my output is like this:
>
> <!-- sip F (ip=170419457,subnet=4294967040) returned is 170419456 -->
> <!-- sip F (ip=170419457,subnet=4294967040) returned is 170419456 -->
> <!-- sip F (ip=3388826225,subnet=4294967280) returned is -906141072 --
> <!-- sip F (ip=3388826225,subnet=4294967280) returned is -906141072 --
> <!-- sip F (ip=170419969,subnet=4294967040) returned is 170419968 -->
>
> <!-- sip F (ip=170419969,subnet=4294967040) returned is 170419968 -->
>
> Where the IP starts 17... the answer is correct. When the value starts
> 3388 the value is wrong.
PHP _outputs_ it as signed integer. Try formatted output to clear
this question:

printf("<!-- sip F (ip=%08X,subnet=%08X) returned is %08X
-->\n",$ip,$subnet,$ans);