socket_create

(PHP 4 >= 4.1.0, PHP 5)

socket_create创建一个套接字(通讯节点)

说明

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

创建并返回一个套接字,也称作一个通讯节点。一个典型的网络连接由 2 个套接字构成,一个运行在客户端,另一个运行在服务器端。

参数

domain

domain 参数指定哪个协议用在当前套接字上。

可用的地址/协议
Domain 描述
AF_INET IPv4 网络协议。TCP 和 UDP 都可使用此协议。
AF_INET6 IPv6 网络协议。TCP 和 UDP 都可使用此协议。
AF_UNIX 本地通讯协议。具有高性能和低成本的 IPC(进程间通讯)。
type

type 参数用于选择套接字使用的类型。

可用的套接字类型
类型 描述
SOCK_STREAM 提供一个顺序化的、可靠的、全双工的、基于连接的字节流。支持数据传送流量控制机制。TCP 协议即基于这种流式套接字。
SOCK_DGRAM 提供数据报文的支持。(无连接,不可靠、固定最大长度).UDP协议即基于这种数据报文套接字。
SOCK_SEQPACKET 提供一个顺序化的、可靠的、全双工的、面向连接的、固定最大长度的数据通信;数据端通过接收每一个数据段来读取整个数据包。
SOCK_RAW 提供读取原始的网络协议。这种特殊的套接字可用于手工构建任意类型的协议。一般使用这个套接字来实现 ICMP 请求(例如 ping)。
SOCK_RDM 提供一个可靠的数据层,但不保证到达顺序。一般的操作系统都未实现此功能。
protocol

protocol 参数,是设置指定 domain 套接字下的具体协议。这个值可以使用 getprotobyname() 函数进行读取。如果所需的协议是 TCP 或 UDP,可以直接使用常量 SOL_TCPSOL_UDP

常见协议
名称 描述
icmp Internet Control Message Protocol 主要用于网关和主机报告错误的数据通信。例如“ping”命令(在目前大部分的操作系统中)就是使用 ICMP 协议实现的。
udp User Datagram Protocol 是一个无连接的、不可靠的、具有固定最大长度的报文协议。由于这些特性,UDP 协议拥有最小的协议开销。
tcp Transmission Control Protocol 是一个可靠的、基于连接的、面向数据流的全双工协议。TCP 能够保障所有的数据包是按照其发送顺序而接收的。如果任意数据包在通讯时丢失,TCP 将自动重发数据包直到目标主机应答已接收。因为可靠性和性能的原因,TCP 在数据传输层使用 8bit 字节边界。因此,TCP 应用程序必须允许传送部分报文的可能。

返回值

socket_create() 正确时返回一个套接字,失败时返回 FALSE。要读取错误代码,可以调用 socket_last_error()。这个错误代码可以通过 socket_strerror() 读取文字的错误说明。

更新日志

版本 说明
5.0.0 增加 AF_INET6 支持。

错误/异常

如果使用一个无效的 domaintypesocket_create() 会使用 AF_INETSOCK_STREAM 替代无效参数,同时会发出 E_WARNING 警告信息。

参见

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User Contributed Notes 11 notes

up
8
kyle gibson
9 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
6
geoff at spacevs dot com
4 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
6
david at eder dot us
10 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
1
jens at surefoot dot com
8 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
2
ab1965 at yandex dot ru
2 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
1
Anonymous
8 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
1
evan at coeus hyphen group dot com
12 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
1
rhollencamp at gmail dot com
5 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
1
Jean Charles MAMMANA
6 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_RAWgetprotobyname('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
6 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
david at eder dot us
9 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;
  }
?>
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