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(PHP 4 >= 4.1.0, PHP 5)
socket_create — Erzeugt einen Socket (Endpunkt für die Kommunikation)
Erzeugt einen Socket (auch als Kommunikations-Endpunkt bezeichnet) und gibt einen Socket-Deskriptor zurück. Ein typisches Netzwerk besteht aus zwei Sockets, von denen der eine die Rolle des Clients und der andere die Rolle des Servers übernimmt.
domain Parameter legt die Protokollfamilie fest, die für die Kommunikation vom Socket benutzt wird.
| Domain | Beschreibung |
|---|---|
| AF_INET | IPv4 basierete Internet-Protokolle. TCP und UDP sind allgemein gebräuchliche Protokolle dieser Familie. |
| AF_INET6 | IPv6 basierete Internet-Protokolle. TCP und UDP sind allgemein gebräuchliche Protokolle dieser Familie. Diese Unterstützung gibt es seit PHP 5.0.0. |
| AF_UNIX | Protokollfamilie für die lokale Kommunikation. Hohe Effizienz und ein geringer Overhead machen sie zur ersten Wahl für die IPC (Inter-Process-Communication). |
Der Parameter type bestimmt den Kommunikationstyp, den der Socket verwenden soll. to be used by the socket.
| Typ | Beschreibung |
|---|---|
| SOCK_STREAM | Stellt zuverlässige, sequentielle verbindungsorientierte Byte-Streams im Vollduplexmodus zur Verfügung. Auch bandexterne Mechanismen zur Datenübertragung können unterstützt werden. Das TCP-Protokoll beruht auf diesem Socket.Typ. |
| SOCK_DGRAM | Unterstützt Datagramme (verbindunglos, Nachrichten vorgegebener Maximallänge, deren Übertragung nicht zuverlässig ist). Das UDP-Protikoll beruht auf diesem Socket-Typ. |
| SOCK_SEQPACKET | Stellt eine zuverlässige, sequentielle. bidirektionale verbindungsorientierte Übertragungsweg für Datagramme vorgegebener Maximallänge zur Verfügung. Ein Empfänger muss bei jeder Leseanforderung das gesamte Datenpaket lesen. |
| SOCK_RAW | Stellt einen Zugang mit einem nicht bestimmten Netzwerkprotokoll zur Verfügung. Dieser spezielle Socket-Typ kann dazu benutzt werden, um manuell ein Protokoll eines beliebigen Typs zu erstellen. Solche Sockets werden üblicherweise benutzt, um ICMP Requests zu senden (wie etwa ping oder traceroute usw.). |
| SOCK_RDM | Stellt eine zuverlässige Schicht für Datagramme zur Verfügung, in der die Reihenfolge der Datagramme nicht garantiert wird. Dies ist in Ihrem Betriebssytem höchstwahrscheinlich nicht implementiert. |
Der Parameter protocol setzt das spezifische Protokoll innerhalb der angegebenen domain, das vom zurückgegebenen Socket für die Kommunikation benutzt wird. Der passende Wert kann ermittelt werden, indem der Name des Protokolls an die Funktion getprotobyname() übergeben wird. Wenn TCP oder UDP gewünscht werden, können auch die entsprechenden Konstanten SOL_TCP und SOL_UDP benutzt werden.
| Name | Beschreibung |
|---|---|
| icmp | Das Internet Control Message Protocol wird hauptsächlich von Gateways und Hosts benutzt, um Kommunikationsfehler bei Datagrammen zu melden. Das Kommando "ping" (das in den meisten modernen Betriebssystemen enthalten ist) ist ein Beispiel für eine Anwendung von ICMP. |
| udp | Das User Datagram Protocol ist ein verbindungsloses, unzuverlässiges Protokoll, mit dem Datensätze fester Länge versendet werden können. Aufgrund dieser geringen Anforderungen braucht UDP nur einen minimalen Protokoll-Overhead. |
| tcp | Das Transmission Control Protocol ist ein zuverlässiges, verbindungsorientiertes, Stream-orientiertes Protokoll für den Vollduplex-Betrieb. Bei TCP ist garantiert, dass alle Datenpakete in derselben Reihenfolge empfangen werden, in der sie gesendet wurden. Falls während der Übertragung ein Datenpaket verlorengeht, wird es von TCP erneut versendet, und zwar solange, bis der Empfängerhost den Eingang dieses Paktes zurückmeldet. Aus Gründen der Zuverlässigkeit und Leistung ist TCP so implementiert, dass es eigenständig die oktalen Grenzen der darunterliegenden Datagramm-Kommunikationschicht bestimmen kann. Aus diesem Grund müssen TCP Anwendungen in der Lage sein, auch Teilübertragungen empfangen zu können. |
Bei Erfolg gibt socket_create() einen Socket-Deskriptor zurück, bei einem Fehler wird FALSE zurückgegeben. Der aktuelle Fehlercode kann mit socket_last_error() ermittelt und an die Funktion socket_strerror() übergeben werden, um eine textuelle Beschreibing des Fehlers zu erhalten.
Falls eine ungültige domain oder ein ungültiger type angegbeben wird, fällt socket_create() auf seinen Standardeinstellungen AF_INET und entsprechend SOCK_STREAM zurück und gibt zusätzlich eine E_WARNING-Meldung aus.
Here is a ping function for PHP without using exec/system/passthrough/etc... Very useful to use to just test if a host is online before attempting to connect to it. Timeout is in seconds.
<?PHP
function ping($host, $timeout = 1) {
/* ICMP ping packet with a pre-calculated checksum */
$package = "\x08\x00\x7d\x4b\x00\x00\x00\x00PingHost";
$socket = socket_create(AF_INET, SOCK_RAW, 1);
socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array('sec' => $timeout, 'usec' => 0));
socket_connect($socket, $host, null);
$ts = microtime(true);
socket_send($socket, $package, strLen($package), 0);
if (socket_read($socket, 255))
$result = microtime(true) - $ts;
else $result = false;
socket_close($socket);
return $result;
}
?>
Note that if you create a socket with AF_UNIX, a file will be created in the filesystem. This file is not removed when you call socket_close - you should unlink the file after you close the socket.
A simple example how to send a raw udp packet
<?php
$frame = array(
array(1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1),
array(1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1),
array(1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,1),
array(1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,1),
array(1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,1),
array(1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,1),
array(1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1),
array(1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1)
);
send_frame($frame, 1500);
/**
* Sends 18x8 MCUF-UDP packet to target host.
*
* see also:
* wiki.blinkenarea.org/index.php/MicroControllerUnitFrame
*
* @param array $frame 18x8 '0' or '1'
* @param int $delay delay in msec
* @param string $host target host
* @param int $port target port (udp)
*/
function send_frame($frame, $delay, $host="192.168.0.23", $port=2323) {
$header = "\x23\x54\x26\x66\x00\x08\x00\x12\x00\x01\x00\xff";
$buf = $header;
for ($i=0;$i<8;$i++) {
for ($j=0;$j<18;$j++) {
if ($frame[$i][$j]) {
$buf.="\xff";
} else {
$buf.="\x00";
}
}
}
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_sendto($socket, $buf, strlen($buf), 0, $host, $port);
socket_close($socket);
usleep($delay*1000);
}
?>
It took some investigation to understand the bit about raw sockets requiring root access and raw sockets being required to perform a seemingly simple "ping" on a Linux server. My source of confusion was that the regular command line "ping" utility did not require me to be root to exec it, so what was the difference? I found the answer starting with a forum posting to look up `man 7 raw` for raw sockets info which reveals:
"Only processes with an effective user ID of 0 or the CAP_NET_RAW capability are allowed to open raw sockets."
So root is not the only way; the ping utility normally works because it has suid permission. There is some interesting source code however that allows you to selectively assign the CAP_NET_RAW capability without the need for suid. Use at your own risk, this is provided for informational purposes only:
http://www.olafdietsche.de/linux/capability/
After weeks of trying to find a PHP network client that supports TFTP and Telnet I finally break down and wrote a client library. You can find it here: http://www.verticalevolution.com/blog/index.php?/pages/PHP-Client.html
This isn't like other telnet libraries that just exec the OS's telnet, it makes and negotiates its own options. It creates the TFTP packets to send data back and forth.
On UNIX systems php needs /etc/protocols for constants like SOL_UDP and SOL_TCP.
This file was missing on my embedded platform.
I've written the ping() function using socket_create() with SOCK_RAW.
(on Unix System, you need to have the root acces to execute this function)
<?php
/// start ping.inc.php ///
$g_icmp_error = "No Error";
// timeout in ms
function ping($host, $timeout)
{
$port = 0;
$datasize = 64;
global $g_icmp_error;
$g_icmp_error = "No Error";
$ident = array(ord('J'), ord('C'));
$seq = array(rand(0, 255), rand(0, 255));
$packet = '';
$packet .= chr(8); // type = 8 : request
$packet .= chr(0); // code = 0
$packet .= chr(0); // checksum init
$packet .= chr(0); // checksum init
$packet .= chr($ident[0]); // identifier
$packet .= chr($ident[1]); // identifier
$packet .= chr($seq[0]); // seq
$packet .= chr($seq[1]); // seq
for ($i = 0; $i < $datasize; $i++)
$packet .= chr(0);
$chk = icmpChecksum($packet);
$packet[2] = $chk[0]; // checksum init
$packet[3] = $chk[1]; // checksum init
$sock = socket_create(AF_INET, SOCK_RAW, getprotobyname('icmp'));
$time_start = microtime();
socket_sendto($sock, $packet, strlen($packet), 0, $host, $port);
$read = array($sock);
$write = NULL;
$except = NULL;
$select = socket_select($read, $write, $except, 0, $timeout * 1000);
if ($select === NULL)
{
$g_icmp_error = "Select Error";
socket_close($sock);
return -1;
}
elseif ($select === 0)
{
$g_icmp_error = "Timeout";
socket_close($sock);
return -1;
}
$recv = '';
$time_stop = microtime();
socket_recvfrom($sock, $recv, 65535, 0, $host, $port);
$recv = unpack('C*', $recv);
if ($recv[10] !== 1) // ICMP proto = 1
{
$g_icmp_error = "Not ICMP packet";
socket_close($sock);
return -1;
}
if ($recv[21] !== 0) // ICMP response = 0
{
$g_icmp_error = "Not ICMP response";
socket_close($sock);
return -1;
}
if ($ident[0] !== $recv[25] || $ident[1] !== $recv[26])
{
$g_icmp_error = "Bad identification number";
socket_close($sock);
return -1;
}
if ($seq[0] !== $recv[27] || $seq[1] !== $recv[28])
{
$g_icmp_error = "Bad sequence number";
socket_close($sock);
return -1;
}
$ms = ($time_stop - $time_start) * 1000;
if ($ms < 0)
{
$g_icmp_error = "Response too long";
$ms = -1;
}
socket_close($sock);
return $ms;
}
function icmpChecksum($data)
{
$bit = unpack('n*', $data);
$sum = array_sum($bit);
if (strlen($data) % 2) {
$temp = unpack('C*', $data[strlen($data) - 1]);
$sum += $temp[1];
}
$sum = ($sum >> 16) + ($sum & 0xffff);
$sum += ($sum >> 16);
return pack('n*', ~$sum);
}
function getLastIcmpError()
{
global $g_icmp_error;
return $g_icmp_error;
}
/// end ping.inc.php ///
?>
to ionic and david...
I'm just taking a stab at this, but wouldn't some combination of gethostbynamel and php_uname('n') provide you with the world-facing IP address without making a system call or using expensive socket operations? Don't get me wrong, socket operations have their place, but if you just need the server IP from a cli script, socket operations seem expensive. :)
<?php
print_r(gethostbynamel(php_uname('n')));
?>
When running these types of sockets, typically you need to be root or else they fail (not the case with stream sockets: http://us.php.net/manual/en/function.stream-socket-server.php)
This is an example for Linux/Unix type systems to use sockets without being root. (tested on Debian and CentOS)
<?php
$user = "daemon";
$script_name = "uid"; //the name of this script
/////////////////////////////////////////////
//try creating a socket as a user other than root
echo "\n__________________________________________\n";
echo "Trying to start a socket as user $user\n";
$uid_name = posix_getpwnam($user);
$uid_name = $uid_name['uid'];
if(posix_seteuid($uid_name))
{
echo "SUCCESS: You are now $user!\n";
if($socket = @socket_create(AF_INET, SOCK_RAW, 1))
{
echo "SUCCESS: You are NOT root and created a socket! This should not happen!\n";
} else {
echo "ERROR: socket_create() failed because you're not root!\n";
}
$show_process = shell_exec("ps aux | grep -v grep | grep $script_name");
echo "Current process stats::-->\t $show_process";
} else {
exit("ERROR: seteuid($uid_name) failed!\n");
}
/////////////////////////////////////////////
//no try creating a socket as root
echo "\n__________________________________________\n";
echo "Trying to start a socket as user 'root'\n";
if(posix_seteuid(0))
{
echo "SUCCESS: You are now root!\n";
$show_process = shell_exec("ps aux | grep -v grep | grep $script_name");
echo "Current process stats::-->\t $show_process";
if($socket = @socket_create(AF_INET, SOCK_RAW, 1))
{
echo "SUCCESS: You created a socket as root and now should seteuid() to another user\n";
/////////////////////////////////////////
//now modify the socket as another user
echo "\n__________________________________________\n";
echo "Switching to user $user\n";
if(posix_seteuid($uid_name))
{
echo "SUCCESS: You are now $user!\n";
if(socket_bind($socket, 0, 8000))
{
echo "SUCCESS: socket_bind() worked as $user!\n";
} else {
echo "ERROR: Must be root to user socket_bind()\n";
}
$show_process = shell_exec("ps aux | grep -v grep | grep $script_name");
echo "Current process stats::-->\t $show_process";
socket_close($socket); //hard to error check but it does close as this user
echo "SUCCESS: You closed the socket as user $user!\n";
} else {
echo "ERROR: seteuid($uid_name) failed while socket was open!\n";
}
} else {
echo "ERROR: Socket failed for some reason!\n";
}
} else {
exit("ERROR: Changing to root failed!\n");
}
?>
To david _at* eder #do; us:
Dependent on your system, you could, at least on LINUX, use exec with "/sbin/ifconfig eth0 | awk '/inet /{ print substr($2,9) }'" (also working for non-root users), that will work a little bit faster as your PHP function.
Though, we should keep in mind that users with safe_mode enabled are more or less forced to use the socket thing. :)
Please be aware that RAW sockets (as used for the ping example) are restricted to root accounts on *nix systems. Since web servers hardly ever run as root, they won't work on webpages.
On Windows based servers it should work regardless.
Here's a ping function that uses sockets instead of exec(). Note: I was unable to get socket_create() to work without running from CLI as root. I've already calculated the package's checksum to simplify the code (the message is 'ping' but it doesn't actually matter).
<?php
function ping($host) {
$package = "\x08\x00\x19\x2f\x00\x00\x00\x00\x70\x69\x6e\x67";
/* create the socket, the last '1' denotes ICMP */
$socket = socket_create(AF_INET, SOCK_RAW, 1);
/* set socket receive timeout to 1 second */
socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array("sec" => 1, "usec" => 0));
/* connect to socket */
socket_connect($socket, $host, null);
/* record start time */
list($start_usec, $start_sec) = explode(" ", microtime());
$start_time = ((float) $start_usec + (float) $start_sec);
socket_send($socket, $package, strlen($package), 0);
if(@socket_read($socket, 255)) {
list($end_usec, $end_sec) = explode(" ", microtime());
$end_time = ((float) $end_usec + (float) $end_sec);
$total_time = $end_time - $start_time;
return $total_time;
} else {
return false;
}
socket_close($socket);
}
?>
Took me about 20 minutes to figure out the proper arguments to supply for a AF_UNIX socket. Anything else, and I would get a PHP warning about the 'type' not being supported. I hope this saves someone else time.
<?php
$socket = socket_create(AF_UNIX, SOCK_STREAM, 0);
// code
?>
Sometimes when you are running CLI, you need to know your own ip address.
<?php
$addr = my_ip();
echo "my ip address is $addr\n";
function my_ip($dest='64.0.0.0', $port=80)
{
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_connect($socket, $dest, $port);
socket_getsockname($socket, $addr, $port);
socket_close($socket);
return $addr;
}
?>
Seems there aren't any examples of UDP clients out there. This is a tftp client. I hope this makes someone's life easier.
<?php
function tftp_fetch($host, $filename)
{
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
// create the request packet
$packet = chr(0) . chr(1) . $filename . chr(0) . 'octet' . chr(0);
// UDP is connectionless, so we just send on it.
socket_sendto($socket, $packet, strlen($packet), 0x100, $host, 69);
$buffer = '';
$port = '';
$ret = '';
do
{
// $buffer and $port both come back with information for the ack
// 516 = 4 bytes for the header + 512 bytes of data
socket_recvfrom($socket, $buffer, 516, 0, $host, $port);
// add the block number from the data packet to the ack packet
$packet = chr(0) . chr(4) . substr($buffer, 2, 2);
// send ack
socket_sendto($socket, $packet, strlen($packet), 0, $host, $port);
// append the data to the return variable
// for large files this function should take a file handle as an arg
$ret .= substr($buffer, 4);
}
while(strlen($buffer) == 516); // the first non-full packet is the last.
return $ret;
}
?>
Okay I talked with Richard a little (via e-mail). We agree that getprotobyname() and using the constants should be the same in functionality and speed, the use of one or the other is merely coding style. Personally, we both think the constants are prettier :).
The eight different protocols are the ones implemented in PHP- not the total number in existance (RFC 1340 has 98).
All we disagree on is using 0- Richard says that "accordning to the official unix/bsd sockets 0 is more than fine." I think that since 0 is a reserved number according to RFC 1320, and when used usually refers to IP, not one of it's sub-protocols (TCP, UDP, etc.)
Actually, you don't need to use
getprotobyname("tcp") but instead can use
the constants: SOL_TCP and SOL_UDP.
Here an extract of the source from
ext/sockets which should make this clear.
if ((pe = getprotobyname("tcp"))) {
REGISTER_LONG_CONSTANT("SOL_TCP", pe->p_proto,
CONST_CS | CONST_PERSISTENT);
}
Normally the third parameter can be set to 0. In the
original BSD Socket implementation the third parameter
(there are 8 different types, here only two) should be
IPPROTO_TCP or IPPROTO_UPD (or one of the 6 others ones).
These two parameters are though not warpped in PHP as
constants and therefore not available.
Please use SOL_TCP and SOL_UDP. e.g.:
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
Please be aware of the fact that UDP
and TCP can only be used with AF_INET which is: "Adress Family Internet". With UNIX Domain sockets TCP/UDP would make no sense!
best regards
-Richard-Moh Samar
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