LXXXII. Network Functions

Wstęp

Wymagania

Do zbudowania tego rozszerzenia nie są wymagane żadne zewnętrzne biblioteki.

Instalacja

By używać tych funkcji, nie trzeba niczego instalować. Są one częścią jądra PHP.

Konfiguracja czasu wykonywania

Na działanie tych funcji wpływają ustawienia zawarte w pliku php.ini.

Tabela 1. Network Configuration Options

Name	Default	Changeable	Changelog
define_syslog_variables	"0"	PHP_INI_ALL

Szczegóły i definicje dotyczące stałych PHP_INI_* znajdują się w rozdziale Dodatek H.

Oto krótkie wyjaśnienie dyrektyw konfiguracji.

define_syslog_variables boolean: Whether or not to define the various syslog variables (e.g. $LOG_PID, $LOG_CRON, etc.). Turning it off is a good idea performance-wise. At runtime, you can define these variables by calling define_syslog_variables().

Typy zasobów

To rozszerzenie nie posiada żadnych rodzajów zasobów.

Stałe predefinopwane

Poniższe stałe są częścią jądra PHP a więc są zawsze widoczne.

Tabela 2. openlog() Options

Constant	Description
LOG_CONS	if there is an error while sending data to the system logger, write directly to the system console
LOG_NDELAY	open the connection to the logger immediately
LOG_ODELAY	(default) delay opening the connection until the first message is logged
LOG_NOWAIT
LOG_PERROR	print log message also to standard error
LOG_PID	include PID with each message

Tabela 3. openlog() Facilities

Constant	Description
LOG_AUTH	security/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined)
LOG_AUTHPRIV	security/authorization messages (private)
LOG_CRON	clock daemon (cron and at)
LOG_DAEMON	other system daemons
LOG_KERN	kernel messages
LOG_LOCAL0 ... LOG_LOCAL7	reserved for local use, these are not available in Windows
LOG_LPR	line printer subsystem
LOG_MAIL	mail subsystem
LOG_NEWS	USENET news subsystem
LOG_SYSLOG	messages generated internally by syslogd
LOG_USER	generic user-level messages
LOG_UUCP	UUCP subsystem

Tabela 4. syslog() Priorities (in descending order)

Constant	Description
LOG_EMERG	system is unusable
LOG_ALERT	action must be taken immediately
LOG_CRIT	critical conditions
LOG_ERR	error conditions
LOG_WARNING	warning conditions
LOG_NOTICE	normal, but significant, condition
LOG_INFO	informational message
LOG_DEBUG	debug-level message

Tabela 5. dns_get_record() Options

Constant	Description
DNS_A	IPv4 Address Resource
DNS_MX	Mail Exchanger Resource
DNS_CNAME	Alias (Canonical Name) Resource
DNS_NS	Authoritative Name Server Resource
DNS_PTR	Pointer Resource
DNS_HINFO	Host Info Resource (See IANA's Operating System Names for the meaning of these values)
DNS_SOA	Start of Authority Resource
DNS_TXT	Text Resource
DNS_ANY	Any Resource Record. On most systems this returns all resource records, however it should not be counted upon for critical uses. Try DNS_ALL instead.
DNS_AAAA	IPv6 Address Resource
DNS_ALL	Iteratively query the name server for each available record type.

Spis treści
checkdnsrr -- Check DNS records corresponding to a given Internet host name or IP address
closelog -- Close connection to system logger
debugger_off -- Disable internal PHP debugger (PHP 3)
debugger_on -- Enable internal PHP debugger (PHP 3)
define_syslog_variables -- Initializes all syslog related constants
dns_check_record -- Synonym for checkdnsrr()
dns_get_mx -- Synonym for getmxrr()
dns_get_record -- Fetch DNS Resource Records associated with a hostname
fsockopen -- Open Internet or Unix domain socket connection
gethostbyaddr -- Get the Internet host name corresponding to a given IP address
gethostbyname -- Get the IP address corresponding to a given Internet host name
gethostbynamel -- Get a list of IP addresses corresponding to a given Internet host name
getmxrr -- Get MX records corresponding to a given Internet host name
getprotobyname -- Get protocol number associated with protocol name
getprotobynumber -- Get protocol name associated with protocol number
getservbyname -- Get port number associated with an Internet service and protocol
getservbyport -- Get Internet service which corresponds to port and protocol
inet_ntop -- Converts a packed internet address to a human readable representation
inet_pton -- Converts a human readable IP address to its packed in_addr representation
ip2long -- Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address
long2ip -- Converts an (IPv4) Internet network address into a string in Internet standard dotted format
openlog -- Open connection to system logger
pfsockopen -- Open persistent Internet or Unix domain socket connection
socket_get_status -- Alias of stream_get_meta_data()
socket_set_blocking -- Alias of stream_set_blocking()
socket_set_timeout -- Alias of stream_set_timeout()
syslog -- Generate a system log message

User Contributed Notes


Regarding samuele's note:



You can get faster code if you apply directly what happens in  network devices, such as routers. If you AND (logic operation) the remote ip against the local netmask the result will be the network ip if the remote ip is from the local network. Example:



    192.168.0.16 = 11000000.10101000.00000000.00010000

& 255.255.255.0 = 11111111.11111111.11111111.00000000

--------------------------------------------------------------

   192.168.0.0 = 11000000.10101000.00000000.00000000



And now the code. My example uses a html form where you place the values you want to test:



<HTML><HEAD><TITLE>Check IP</TITLE>

</HEAD><BODY>

    <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST">



Hope you find this useful.

        IP to check: <input type="text" name="ip"> <br>

        Local network ip: <input type="text" name="net"> <br>

        Local netmask: <input type="text" name="mask"> <br>

        <input type="submit" name="check" value="Check it!">

    </form>

    <?php



/**

 * @param string $ip IP to check in dotted decimal format

 * @param string $net Network IP in dotted decimal format

 * @param string $mask Netmask in dotted decimal format

 * @returns true if the ip belongs to the network, false otherwise

 **/

function isIPIn($ip, $net, $mask) {

    //doesn't check for the return value of ip2long

    $ip = ip2long($_POST['ip']);

    $rede = ip2long($_POST['net']);

    $mask = ip2long($_POST['mask']);

    

    //AND 

    $res = $ip & $mask;

    

    return ($res == $rede);

}



if (isset($_POST['check'])) {

     echo isIPIn($_POST['ip'], $_POST['net'], $_POST['mask']) ? "IP IN.": "IP OUT.";

}

 ?>

</BODY><HTML>


To find if an IP is in a net/mask (very fast):

<?php

function isIPIn($ip,$net,$mask) {

   $lnet=ip2long($net);

   $lip=ip2long($ip);

   $binnet=str_pad( decbin($lnet),32,"0","STR_PAD_LEFT" );

   $firstpart=substr($binnet,0,$mask);

   $binip=str_pad( decbin($lip),32,"0","STR_PAD_LEFT" );

   $firstip=substr($binip,0,$mask);

   return(strcmp($firstpart,$firstip)==0);

   }

?>



This function can be compacted, avoiding some variable settings, but the function will not be too clear to read...

Example code, used to made a kind of location service network-based:



<?php

$n = array ( "192.168.0.0/16"   => "TUSCANY",

             "192.168.1.0/24"   => "- Florence",

             "192.168.2.0/24"   => "- Pisa",

             "192.168.3.0/24"   => "- Siena",

             "192.168.64.0/21" => "- Tuscan Archipelago",

             "192.168.64.0/23" => "--- Elba Island",

             "192.168.66.0/24" => "--- Capraia Island",

             "192.168.67.0/24" => "--- Giannutri Island");



// Normally you should use the following line

$myip = $HTTP_SERVER_VARS['REMOTE_ADDR'];

// This is first example: returns Tuscany/Pisa

$myip = "192.168.2.33";

// This is second example: returns Tuscany/T.Arch./Elba

$myip = "192.168.65.34";



echo "Your position:<br />\n";

foreach ( $n as $k=>$v ) {

   list($net,$mask)=split("/",$k);

   if (isIPIn($myip,$net,$mask)) {

       echo $n[$k]."<br />\n"; }

   }

?>



and so on...


Previous example of IP range to CIDR list does not cope with ranges as well as the perl Net::Netmask range2cidrlist() function. In PHP this looks like



<?

function imask($this)

{

// use base_convert not dechex because dechex is broken and returns 0x80000000 instead of 0xffffffff

return base_convert((pow(2,32) - pow(2, (32-$this)))), 10, 16);

}



function imaxblock($ibase, $tbit)

{

while ($tbit > 0)

{

$im = hexdec(imask($tbit-1));

$imand = $ibase & $im;

if ($imand != $ibase)

{

break;

}

$tbit--;

}

return $tbit;

}



function range2cidrlist($istart, $iend)

{

// this function returns an array of cidr lists that map the range given

$s = explode(".", $istart);

// PHP ip2long does not handle leading zeros on IP addresses! 172.016 comes back as 172.14, seems to be treated as octal!

$start = "";

$dot = "";

while (list($key,$val) = each($s))

{

$start = sprintf("%s%s%d",$start,$dot,$val);

$dot = ".";

}

$end = "";

$dot = "";

$e = explode(".",$iend);

while (list($key,$val) = each($e))

{

$end = sprintf("%s%s%d",$end,$dot,$val);

$dot = ".";

}

$start = ip2long($start);

$end = ip2long($end);

$result = array();

while ($end > $start)

{

$maxsize = imaxblock($start,32);

$x = log($end - $start + 1)/log(2);

$maxdiff = floor(32 - floor($x));

$ip = long2ip($start);

if ($maxsize < $maxdiff)

{

$maxsize = $maxdiff;

}

array_push($result,"$ip/$maxsize");

$start += pow(2, (32-$maxsize));

}

return $result;

}

?>