ID: 40674
User updated by: matth at mystictrd dot com
Reported By: matth at mystictrd dot com
-Status: Feedback
+Status: Open
Bug Type: Sockets related
Operating System: Debian 3.1
PHP Version: 5.2.1
New Comment:
My first message had a working example but here it is again with more
information.
The purpose is to see DHCP requests from a DHCP Client. So use a DHCP
Client to get an IP address on a system thats on the same network that
this script is running on.
This first example WON'T see the packets:
<?php
$ip = "ENTER YOUR IP ADDRESS HERE"; //example: 192.168.0.100
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_bind($socket, $ip, 67);
while(1)
{
if($src = @socket_recv($socket, $data, 9999, 0)) { echo "data!\n"; }
}
?>
This second example WILL see the packets:
<?php
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_bind($socket, 0, 67);
while(1)
{
if($src = @socket_recv($socket, $data, 9999, 0)) { echo "data!\n"; }
}
?>
This reference might give you a better idea of what I'm talking about:
http://en.wikipedia.org/wiki/Dhcp#DHCP_discovery
Previous Comments:
------------------------------------------------------------------------
[2007-03-06 11:26:47] [EMAIL PROTECTED]
Thank you for this bug report. To properly diagnose the problem, we
need a short but complete example script to be able to reproduce
this bug ourselves.
A proper reproducing script starts with <?php and ends with ?>,
is max. 10-20 lines long and does not require any external
resources such as databases, etc. If the script requires a
database to demonstrate the issue, please make sure it creates
all necessary tables, stored procedures etc.
Please avoid embedding huge scripts into the report.
------------------------------------------------------------------------
[2007-03-02 20:24:54] matth at mystictrd dot com
The way it seems this should work (I easily could be completely off
base) is:
socket_bind could be defined as:
bool socket_bind ( resource $socket, string $address [, int $port [,
string $mac or $iface ]] )
------------------------------------------------------------------------
[2007-03-02 17:21:23] matth at mystictrd dot com
I believe in C/C++ you can specify hardware addresses to listen on -
specifically either a MAC address/an interface name (eth0 in linux).
After doing some tests in C it seems that if you listen on an ip (i.e.
192.168.0.1) and you will not see that type of packet but if you listen
on 0.0.0.0 or INADDR_ANY you can see it.
------------------------------------------------------------------------
[2007-03-01 17:38:01] matth at mystictrd dot com
Ignore my previous workaround example, it did not work as expected.
------------------------------------------------------------------------
[2007-03-01 17:25:57] matth at mystictrd dot com
The reason why is if you take a normal DHCP server you can typically
listen on multiple interfaces. If one wanted to know what interface is
receiving the data you would think to bind on the interfaces IP address.
But since you cannot see that type of packet binding to an IP like that
you must bind to 0 or 0.0.0.0 which doesn't help with knowing what
interface recieved the data since the data does not contain information
about interface mac/ip destination from the client. I'm not positive if
this is a PHP issue or not but I believe you can do it in C/C++ and
that you should be able to do it with PHP. A work around I'm
experimenting with goes as:
<?php
$interface_ip = "10.66.66.1";
$interface_port = 67;
//listens for dhcp requests
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
//you must bind to 0.0.0.0 to actually see anything
socket_bind($socket, 0, 67);
while(1)
{
if($src = @socket_recvfrom($socket, $data, 9999, 0, $interface_ip,
$interface_port))
{
echo "data!\n";
}
}
?>
------------------------------------------------------------------------
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the rest of the comments, please view the bug report online at
http://bugs.php.net/40674
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