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socket_create

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

socket_createCrear un socket (extremo de comunicación)

Descripción

socket_create(int $domain, int $type, int $protocol): resource

Crea y devuelve un recurso socket, también referido como un extremo de comunicación. Una conexión típica de red está constituida por 2 sockets, uno realizando el papel del cliente, y otro realizando el papel del servidor.

Parámetros

domain

El parámetro domain especifica la familia de protocolos que va a usar por el socket.

Available address/protocol families
Dominio Descripción
AF_INET Protocolos basados en Internet IPv4. TCP y UDP son protocolos comunes de esta familia de protocolos.
AF_INET6 Protocolos basados en Internet IPv6. TCP y UDP son protocolos comunes de esta familia de protocolos.
AF_UNIX Familia de protocolos de comunicación local. Alta eficacia y baja sobrecarga la hacen una gran forma de IPC (Interprocess Communication - Comunicación entre procesos).
type

El parámetro type selecciona el tipo de comunicación que va a usar el socket.

Tipos de sockets disponibles
Tipo Descripción
SOCK_STREAM Proporciona flujos de bytes orientados a conexión, secuenciados, fiables y full-duplex. Puede soportar un mecanismo de transmisión fuera de banda. El protocolo TCP está basado en este tipo de socket.
SOCK_DGRAM Soporta datagramas (no orientado a conexión, mensajes no fiables de una longitud máxima). El protocolo UDP está basado en este tipo de socket.
SOCK_SEQPACKET Proporciona una ruta de transmisión de datos orientada a conexión secuenciada, fiable, de dos direcciones para datagramas de longitud máxima fija; se requiere un consumidor para leer un paquete entero con cada llamada de lectura.
SOCK_RAW Proporciona acceso al protocolo de red sin formato. Este tipo especial de socket se puede usar para construir manualmente cualquier tipo de protocolo. Un uso común para este socket es realizar solicitudes ICMP (como ping).
SOCK_RDM Proporcional una capa de datagramas fiable que no garantiza el orden. Lo más seguro es que esto no esté implementado en su sistema operativo.
protocol

El parámetro protocol establece el protocolo específico dentro del domain especificado a usar al comunicarse con el socket devuelto. El valor apropiado puede ser recuperado por su nombre usando getprotobyname(). Si el protocolo deseado es TCP o UDP, también se pueden usar las constantes SOL_TCP, y SOL_UDP correspondientes.

Protocolos comunes
Nombre Descripción
icmp Internet Control Message Protocol (Protocolo de Mensajes de Control de Internet) es usado principalmente por pasarelas y hosts para notificar errores en la comunicación por datagramas. El comando "ping" (presente en la mayoría de los sistemas operativos modernos) es un ejemplo de la aplicación del ICMP.
udp User Datagram Protocol (Protocolo de Datagramas de Usuario) es un protocolo no orientado a conexión, no fiable, con longitud de registros fija. A causa de estos aspectos, UDP requiere una cantidad mínima de sobrecarga del protocolo.
tcp Transmission Control Protocol (Protocolo de Control de Transmisión) es un protocolo fiable orientado a conexión, orientado a flujo, full duplex. TCP garantiza que todos los paquetes de datos serán recibidos en el orden en el que fueron enviados. Si algún paquete se pierde por alguna razón durante la comunicación, TCP automáticamente retransmitirá el paquete hasta que el host destino adminta ese paquete. Por razones de fiabilidad y rendimiento, la implementación de TCP decide por sí misma los límites apropiados de los octetos de la capa de comunicación de datagramas subyacente. Por lo tanto, las aplicaciones TCP deben tener en cuenta la posibilidad de transmisión de resgistros parciales.

Valores devueltos

socket_create() devuelve un recurso socket en caso de éxito, o false en caso de error. El código de error real se puede recuperar llamando a socket_last_error(). Este código de error se puede pasar a socket_strerror() para obtener una explicación textual del error.

Errores/Excepciones

Si se da un domain o type no válido, socket_create() los pone por defecto a AF_INET y SOCK_STREAM respectivamente y además emite un mensaje E_WARNING.

Ver también

add a note

User Contributed Notes 12 notes

up
40
kyle gibson
18 years ago
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
?>
up
10
rhollencamp at gmail dot com
14 years ago
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.
up
8
ab1965 at yandex dot ru
11 years ago
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";
?>
up
3
geoff at spacevs dot com
13 years ago
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;
}
?>
up
-1
Jean Charles MAMMANA
16 years ago
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 ///
?>
up
-1
alexander dot krause at ed-solutions dot de
16 years ago
On UNIX systems php needs /etc/protocols for constants like SOL_UDP and SOL_TCP.

This file was missing on my embedded platform.
up
-1
jens at surefoot dot com
17 years ago
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.
up
-1
evan at coeus hyphen group dot com
22 years ago
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.)
up
-4
david at eder dot us
19 years ago
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;
}
?>
up
-3
Anonymous
18 years ago
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);
}

?>
up
-5
david at eder dot us
19 years ago
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;
}
?>
up
-4
Sakrizz
7 years ago
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);
}

?>
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