(PHP 4 >= 4.1.0, PHP 5, PHP 7)
socket_bind — Binds a name to a socket
$socket
, string $address
[, int $port = 0
] )
Binds the name given in address to the socket
described by socket. This has to be done before
a connection is be established using socket_connect()
or socket_listen().
socketA valid socket resource created with socket_create().
address
If the socket is of the AF_INET family, the
address is an IP in dotted-quad notation
(e.g. 127.0.0.1).
If the socket is of the AF_UNIX family, the
address is the path of a
Unix-domain socket (e.g. /tmp/my.sock).
port (Optional)
The port parameter is only used when
binding an AF_INET socket, and designates
the port on which to listen for connections.
Returns TRUE on success or FALSE on failure.
The error code can be retrieved with socket_last_error(). This code may be passed to socket_strerror() to get a textual explanation of the error.
Example #1 Using socket_bind() to set the source address
<?php
// Create a new socket
$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
// An example list of IP addresses owned by the computer
$sourceips['kevin'] = '127.0.0.1';
$sourceips['madcoder'] = '127.0.0.2';
// Bind the source address
socket_bind($sock, $sourceips['madcoder']);
// Connect to destination address
socket_connect($sock, '127.0.0.1', 80);
// Write
$request = 'GET / HTTP/1.1' . "\r\n" .
'Host: example.com' . "\r\n\r\n";
socket_write($sock, $request);
// Close
socket_close($sock);
?>
Note:
This function must be used on the socket before socket_connect().
Note:
Windows 9x/ME compatibility note: socket_last_error() may return an invalid error code if trying to bind the socket to a wrong address that does not belong to your machine.
If you want to reuse address and port, and get rid of error: unable to bind, address already in use, you have to use socket_setopt (check actual spelling for this function in you PHP verison) before calling bind:
<?php
if (!socket_set_option($sock, SOL_SOCKET, SO_REUSEADDR, 1)) {
echo socket_strerror(socket_last_error($sock));
exit;
}
?>
This solution was found by
Christophe Dirac. Thank you Christophe!
Regarding previous post:
"0" has address is no different from "0.0.0.0"
127.0.0.1 -> accept only from local host
w.x.y.z (valid local IP) -> accep only from this network
0.0.0.0 -> accept from anywhere
Use 0 for port to bind a random (free) port for incoming connections:
socket_bind ($socket, $bind_address, 0);
socket_getsockname($socket, $socket_address, $socket_port);
socket_listen($socket);
...
$socket_port contains the assigned port, you might want to send it to a remote client connecting. Tested with php 5.03.
The aforementioned tidbit about using NULL to bind to all addresses did not work for me, as I would receive an error about unknown address. Using a 0 worked for me:
socket_bind ($socket, 0, $port)
This also allows you to receive UDP broadcasts, which is what I had been trying to figure out.
When doing Unix sockets, it might be necessary to chmod the socket file so as to give Write permission to Group and/or Others. Otherwise, only the owner is allowed to write data into the stream.
Example:
<?php
$sockpath = '/tmp/my.sock';
socket_bind($socket, $sockpath);
//here: write-only (socket_send) to others, only owner can fetch data.
chmod($sockpath, 0702);
?>
It appears for the $address parameter:
'127.0.0.1'
accepts clients from localhost (eg. 127.0.0.1)
'0.0.0.0'
accepts clients from localhost, and the server's network (eg. 127.0.0.1, 192.168.2.5, 10.20.30.40)
'0' or 0
accepts clients from localhost, the server's network, and external networks (eg. 127.0.0.1, 192.168.2.5, 10.20.30.40, 209.85.169.99)
