(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
socket_create — Crea un socket
socket_create() crea un punto de comunicación (un socket) y devuelve una instancia de Socket Una conexión típica de red está compuesta por dos sockets: uno que actúa como cliente y otro como servidor.
domain
El argumento domain especifica la familia
de protocolos a utilizar por el socket.
| Dominio | Descripción |
|---|---|
AF_INET |
Protocolo basado en IPv4. TCP y UDP son los protocolos comunes de esta familia de protocolos. |
AF_INET6 |
Protocolo basado en IPv6. TCP y UDP son los protocolos comunes de esta familia de protocolos. El soporte fue añadido en PHP 5.0.0. |
AF_UNIX |
Familia de protocolos de comunicación local. El alto rendimiento
y los menores costos adicionales lo hacen una gran fuerza de IPC
(Interprocess Communication).
|
type
El argumento type selecciona el tipo de
comunicación a utilizar por el socket.
| Tipo | Descripción |
|---|---|
SOCK_STREAM |
Proporciona flujos de bytes ordenados, fiables, full-duplex,
conectados en base. Un mecanismo de transmisión de datos
"out-of-band" puede ser soportado.
El protocolo TCP se basa en este tipo de sockets.
|
SOCK_DGRAM |
Soporte para datagramas (menos conexión, mensaje no garantizado de longitud máxima fija). El protocolo UDP se basa en este tipo de sockets. |
SOCK_SEQPACKET |
Proporciona un camino de transmisión de datos secuencial, fiable, conectado en base por dos caminos para los datagramas de longitud máxima fija; un consumidor es requerido para leer la totalidad de un paquete con cada llamada a la lectura. |
SOCK_RAW |
Proporciona acceso bruto de protocolo de red. Este tipo especial de socket puede ser utilizado para construir manualmente cualquier tipo de protocolo. Un uso común de este tipo de sockets es el procesamiento de las peticiones ICMP (como el ping). |
SOCK_RDM |
Proporciona una capa fiable de datagrama que no garantiza el orden de los datos. Este tipo de socket es el más probable de no estar implementado en su sistema operativo. |
protocol
El argumento protocol define el protocolo
específico para el dominio domain a utilizar
durante las comunicaciones en un socket devuelto. El valor apropiado
puede ser encontrado por su nombre utilizando la función
getprotobyname(). Si el protocolo deseado es TCP
o UDP, las constantes correspondientes SOL_TCP
y SOL_UDP pueden ser utilizadas.
| Nombre | Descripción |
|---|---|
icmp |
El protocolo ICMP (Internet Control Message
Protocol) es utilizado primero por las
pasarelas y los hosts para reportar errores en
comunicaciones de datagrama. El comando
"ping" (presente en los sistemas
modernos) es un ejemplo de aplicación
utilizando el protocolo ICMP.
|
udp |
El protocolo UDP (User Datagramm Protocol)
es un protocolo sin conexión, incierto con longitudes
de registros fijas. Por lo tanto, UDP
requiere una cantidad mínima de protocolo aéreo.
|
tcp |
El protocolo TCP (Transmission Control Protocol)
es un protocolo fiable, conectado en base, orientado a flujo y
full-duplex. TCP garantiza que cada paquete es
recibido en el orden en que fue enviado. Si algunos paquetes
se pierden durante la comunicación, TCP
retransmitirá estos paquetes hasta que el host destinatario
los haya recibido completamente. Por razones de fiabilidad y
rendimiento, la implementación TCP, ella misma,
decide las fronteras apropiadas de bytes de la capa fundamental
de comunicación del datagrama. Por lo tanto, las aplicaciones
TCP deben permitir la posibilidad de
transmisión parcial de registros.
|
socket_create() devuelve una instancia de
Socket en caso de éxito y false en caso contrario.
El código de error generado puede ser obtenido llamando a la función
socket_last_error(). Este código de error
puede ser pasado a la función socket_strerror()
para obtener un mensaje de error legible por humanos.
Si un valor inválido es especificado en el argumento domain o
en el argumento type, la función socket_create()
tomará como argumentos por defecto respectivamente AF_INET y
SOCK_STREAM y generará un mensaje de advertencia
(E_WARNING).
| Versión | Descripción |
|---|---|
| 8.0.0 | En caso de éxito, esta función devuelve ahora una instancia de Socket; anteriormente, se devolvía un resource. |
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
?>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.It took some time to understand how one PHP process can communicate with another by means of unix udp sockets. Examples of 'server' and 'client' code are given below. Server is assumed to run before client starts.
'Server' code
<?php
if (!extension_loaded('sockets')) {
die('The sockets extension is not loaded.');
}
// create unix udp socket
$socket = socket_create(AF_UNIX, SOCK_DGRAM, 0);
if (!$socket)
die('Unable to create AF_UNIX socket');
// same socket will be used in recv_from and send_to
$server_side_sock = dirname(__FILE__)."/server.sock";
if (!socket_bind($socket, $server_side_sock))
die("Unable to bind to $server_side_sock");
while(1) // server never exits
{
// receive query
if (!socket_set_block($socket))
die('Unable to set blocking mode for socket');
$buf = '';
$from = '';
echo "Ready to receive...\n";
// will block to wait client query
$bytes_received = socket_recvfrom($socket, $buf, 65536, 0, $from);
if ($bytes_received == -1)
die('An error occured while receiving from the socket');
echo "Received $buf from $from\n";
$buf .= "->Response"; // process client query here
// send response
if (!socket_set_nonblock($socket))
die('Unable to set nonblocking mode for socket');
// client side socket filename is known from client request: $from
$len = strlen($buf);
$bytes_sent = socket_sendto($socket, $buf, $len, 0, $from);
if ($bytes_sent == -1)
die('An error occured while sending to the socket');
else if ($bytes_sent != $len)
die($bytes_sent . ' bytes have been sent instead of the ' . $len . ' bytes expected');
echo "Request processed\n";
}
?>
'Client' code
<?php
if (!extension_loaded('sockets')) {
die('The sockets extension is not loaded.');
}
// create unix udp socket
$socket = socket_create(AF_UNIX, SOCK_DGRAM, 0);
if (!$socket)
die('Unable to create AF_UNIX socket');
// same socket will be later used in recv_from
// no binding is required if you wish only send and never receive
$client_side_sock = dirname(__FILE__)."/client.sock";
if (!socket_bind($socket, $client_side_sock))
die("Unable to bind to $client_side_sock");
// use socket to send data
if (!socket_set_nonblock($socket))
die('Unable to set nonblocking mode for socket');
// server side socket filename is known apriori
$server_side_sock = dirname(__FILE__)."/server.sock";
$msg = "Message";
$len = strlen($msg);
// at this point 'server' process must be running and bound to receive from serv.sock
$bytes_sent = socket_sendto($socket, $msg, $len, 0, $server_side_sock);
if ($bytes_sent == -1)
die('An error occured while sending to the socket');
else if ($bytes_sent != $len)
die($bytes_sent . ' bytes have been sent instead of the ' . $len . ' bytes expected');
// use socket to receive data
if (!socket_set_block($socket))
die('Unable to set blocking mode for socket');
$buf = '';
$from = '';
// will block to wait server response
$bytes_received = socket_recvfrom($socket, $buf, 65536, 0, $from);
if ($bytes_received == -1)
die('An error occured while receiving from the socket');
echo "Received $buf from $from\n";
// close socket and delete own .sock file
socket_close($socket);
unlink($client_side_sock);
echo "Client exits\n";
?>Here is a ping function for PHP without using exec/system/passthrough/etc... Very useful to use to just test if a host is online before attempting to connect to it. Timeout is in seconds.
<?PHP
function ping($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;
}
?>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 $g_icmp_error;
}
/// end ping.inc.php ///
?>On UNIX systems php needs /etc/protocols for constants like SOL_UDP and SOL_TCP.
This file was missing on my embedded platform.Please be aware that RAW sockets (as used for the ping example) are restricted to root accounts on *nix systems. Since web servers hardly ever run as root, they won't work on webpages.
On Windows based servers it should work regardless.Seems there aren't any examples of UDP clients out there. This is a tftp client. I hope this makes someone's life easier.
<?php
function tftp_fetch($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 $ret;
}
?>Here's a ping function that uses sockets instead of exec(). Note: I was unable to get socket_create() to work without running from CLI as root. I've already calculated the package's checksum to simplify the code (the message is 'ping' but it doesn't actually matter).
<?php
function ping($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);
}
?>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.)Here's a solution for icmpv6 ping with php, dropping it here in case if someone has problems with icmpv6 with php.
<?php
$host = "2a03:2880:f11b:83:face:b00c:0:25de";
$timeout = 100000;
$count = 3;
echo "Latency: ". round(1000 * pingv6($host,$timeout,$count),5) ." ms \n";
function pingv6($target,$timeout,$count) {
echo "target is ipv6 address, ". getprotobyname('ipv6-icmp'). " \n";
/* create the socket, the last '1' denotes ICMP */
$socket = socket_create(AF_INET6, SOCK_RAW, getprotobyname('ipv6-icmp'));
/* set socket receive timeout to 1 second */
$sec=intval($timeout/1000);
$usec=$timeout%1000*1000;
socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array("sec"=>$sec, "usec"=>$usec));
/* socket package parameters */
$type = "\x80";
$seqNumber = chr(floor($i/256)%256) . chr($i%256);
$checksum= "\x00\x00";
$code = "\x00";
$identifier = chr(rand(0,255)) . chr(rand(0,255));
$msg = "!\"#$%&'()*+,-./1234567";
$package = $type.$code.$checksum.$identifier.$seqNumber.$msg;
$checksum = icmpChecksum($package);
$package = $type.$code.$checksum.$identifier.$seqNumber.$msg;
/* socket connect */
if(@socket_connect($socket, $target, null)){
for($i = 0; $i < $count; $i++){
list($start_usec, $start_sec) = explode(" ", microtime());
$start_time = ((float) $start_usec + (float) $start_sec);
$startTime = microtime(true);
socket_send($socket, $package, strLen($package), 0);
while ($startTime + $timeout*1000 > microtime(true)){
if(socket_read($socket, 255) !== false) {
list($end_usec, $end_sec) = explode(" ", microtime());
$end_time = ((float) $end_usec + (float) $end_sec);
$total_time = $end_time - $start_time;
echo "round trip time (".$i."): ". $total_time ."\n";
return $total_time;
break;
}else{
return "null";
echo "Timed out (".$i."), Got no echo reply\n";
break;
}
}
usleep($interval*1000);
}
socket_close($socket);
}
}
function icmpChecksum($data){
if (strlen($data)%2) $data .= "\x00";
$bit = unpack('n*', $data);
$sum = array_sum($bit);
while ($sum >> 16)
$sum = ($sum >> 16) + ($sum & 0xffff);
return pack('n*', ~$sum);
}
?>