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Last updated: Thu, 21 Aug 2003

LXVI. Network Functions

Introduction

Requirements

No external libraries are needed to build this extension.

Installation

There is no installation needed to use these functions; they are part of the PHP core.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 1. Network Configuration Options

NameDefaultChangeable
define_syslog_variables"0"PHP_INI_ALL
For further details and definition of the PHP_INI_* constants see ini_set().

Here's a short explanation of the configuration directives.

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().

Resource Types

This extension has no resource types defined.

Predefined Constants

The constants below are always available as part of the PHP core.

Table 2. openlog() Options

ConstantDescription
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_PERRORprint log message also to standard error
LOG_PIDinclude PID with each message

Table 3. openlog() Facilities

ConstantDescription
LOG_AUTH security/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined)
LOG_AUTHPRIVsecurity/authorization messages (private)
LOG_CRONclock daemon (cron and at)
LOG_DAEMONother system daemons
LOG_KERNkernel messages
LOG_LOCAL0 ... LOG_LOCAL7reserved for local use, these are not available in Windows
LOG_LPRline printer subsystem
LOG_MAILmail subsystem
LOG_NEWSUSENET news subsystem
LOG_SYSLOGmessages generated internally by syslogd
LOG_USERgeneric user-level messages
LOG_UUCPUUCP subsystem

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

ConstantDescription
LOG_EMERGsystem is unusable
LOG_ALERTaction must be taken immediately
LOG_CRITcritical conditions
LOG_ERRerror conditions
LOG_WARNINGwarning conditions
LOG_NOTICEnormal, but significant, condition
LOG_INFOinformational message
LOG_DEBUGdebug-level message

Table 5. dns_get_record() Options

ConstantDescription
DNS_AIPv4 Address Resource
DNS_MXMail Exchanger Resource
DNS_CNAMEAlias (Canonical Name) Resource
DNS_NSAuthoritative Name Server Resource
DNS_PTRPointer Resource
DNS_HINFOHost Info Resource (See IANA's Operating System Names for the meaning of these values)
DNS_SOAStart of Authority Resource
DNS_TXTText Resource
DNS_ANYAny 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_AAAAIPv6 Address Resource
DNS_ALLItteratively query the name server for each available record type.
Table of Contents
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
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 for stream_set_blocking()
socket_set_timeout -- Alias for stream_set_timeout()
syslog -- Generate a system log message


add a note add a note User Contributed Notes
Network Functions
null at tty dot net dot ru
13-Oct-2003 06:51
Ported Net::Netmask perl module:
http://null.pp.ru/src/php/Netmask.phps
anderson at piq dot com dot br
07-Aug-2003 12:10
If you want to get the interface of an IP, based on the local route table, use this.

function GetIfaceforIP($user_ip)
{
    $route = "/bin/netstat -rn";

    exec($route, $aoutput);
    foreach($aoutput as $key => $line)
    {
        if($key > 1)
        {
            $line = ereg_replace("[[:space:]]+",",",$line);
            list($network, $gateway, $mask, $flags, $mss, $window, $irtt, $iface) = explode(",", $line)
            if((ip2long($user_ip) & ip2long($mask)) == ip2long($network))
            {
                return $iface;
            }
        }
    }
}
03-Apr-2003 11:11
Alternative cidr_conv function - a little easier to follow

function cidr_conv($cidr_address) {
  $first = substr($cidr_address, 0, strpos($cidr_address, "/"));
  $netmask = substr(strstr($cidr_address, "/"), 1);

  $first_bin = str_pad(decbin(ip2long($first)), 32, "0", STR_PAD_LEFT);
  $netmask_bin = str_pad(str_repeat("1", (integer)$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 "$first - $last";
}
trevor-hemsley at nospam dot dial dot pipex dot com
17-Oct-2002 01:53
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)))), 1016);
}

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;
}
?>
philippe-at-cyberabuse.org
13-Oct-2002 05:49
... and this one will do the opposite (o return NULL for invalid netblocks) :

1.0.0.0 1.0.255.255 -> 1.0.0.0/16
1.0.0.0 1.3.255.255 -> 1.0.0.0/14
192.168.0.0 192.168.0.255 -> 192.168.0.0/24

function ip2cidr($ip_start,$ip_end) {
if(long2ip(ip2long($ip_start))!=$ip_start or long2ip(ip2long($ip_end))!=$ip_end) return NULL;
$ipl_start=(int)ip2long($ip_start);
$ipl_end=(int)ip2long($ip_end);
if($ipl_start>0 && $ipl_end<0) $delta=($ipl_end+4294967296)-$ipl_start;
else $delta=$ipl_end-$ipl_start;
$netmask=str_pad(decbin($delta),32,"0","STR_PAD_LEFT");
if(ip2long($ip_start)==0 && substr_count($netmask,"1")==32) return "0.0.0.0/0";
if($delta<0 or ($delta>0 && $delta%2==0)) return NULL;
for($mask=0;$mask<32;$mask++) if($netmask[$mask]==1) break;
if(substr_count($netmask,"0")!=$mask) return NULL;
return "$ip_start/$mask";
}
philippe-at-cyberabuse.org
15-Dec-2001 11:46
PHP miss CIDR functions.

This one will convert a CIDR like this:
0.0.0.0/16 -> 0.0.0.0 - 0.0.255.255
127.0/16 -> 127.0.0.0 - 127.0.255.255
etc...

function cidrconv($net) {
$start=strtok($net,"/");
$n=3-substr_count($net, ".");
if ($n>0) { for ($i=$n;$i>0;$i--) $start.=".0"; }
$bits1=str_pad(decbin(ip2long($start)),32,"0","STR_PAD_LEFT");
$net=pow(2,(32-substr(strstr($net,"/"),1)))-1;
$bits2=str_pad(decbin($net),32,"0","STR_PAD_LEFT");
for ($i=0;$i<32;$i++) {
if ($bits1[$i]==$bits2[$i]) $final.=$bits1[$i];
if ($bits1[$i]==1 and $bits2[$i]==0) $final.=$bits1[$i];
if ($bits1[$i]==0 and $bits2[$i]==1) $final.=$bits2[$i];
}
return $start." - ".long2ip(bindec($final));
}
philip at cornado dot c()m
05-Jul-2001 04:20
More socket functions can be seen here :
http://www.php.net/manual/en/ref.sockets.php

<muscat_setupcheckdnsrr>
 Last updated: Thu, 21 Aug 2003
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