I'm using the latest PHP. I downloaded and compiled it yesterday :-)
about sockets.... yes UDP is an option since in the manual it quotes:
fsockopen
(PHP3 , PHP4 )
fsockopen -- Open Internet or Unix domain socket connection
Description
int fsockopen (string [udp://]hostname, int port [, int errno [, string errstr [, double timeout]]])
Initiates a stream connection in the Internet (AF_INET, using TCP or UDP) or Unix (AF_UNIX) domain. For the Internet
domain, it will open a TCP socket connection to hostname on port port. hostname may in this case be either a fully qualified
domain name or an IP address. For UDP connections, you need to explicitely specify the the protocol: udp://hostname. For
the Unix domain, hostname will be used as the path to the socket, port must be set to 0 in this case. The optional timeout can
be used to set a timeout in seconds for the connect system call.
Fsockopen() returns a file pointer which may be used together with the other file functions (such as fgets(), fgetss(),
fputs(), fclose(), and feof()).
If the call fails, it will return false and if the optional errno and errstr arguments are present they will be set to indicate the
actual system level error that occurred on the system-level connect() call. If the returned errno is 0 and the function
returned false, it is an indication that the error occurred before the connect() call. This is most likely due to a problem
initializing the socket. Note that the errno and errstr arguments must be passed by reference.
Depending on the environment, the Unix domain or the optional connect timeout may not be available.
The socket will by default be opened in blocking mode. You can switch it to non-blocking mode by using
socket_set_blocking().
Example 1. Fsockopen() Example
$fp = fsockopen ("www.php.net", 80, &$errno, &$errstr, 30);
if (!$fp) {
echo "$errstr ($errno)<br>\n";
} else {
fputs ($fp, "GET / HTTP/1.0\r\n\r\n");
while (!feof($fp)) {
echo fgets ($fp,128);
}
fclose ($fp);
}
The example below shows how to retrieve the day and time from the UDP service "daytime" (port 13) in your own machine.
Example 2. Using UDP connection
<?php
$fp = fsockopen("udp://127.0.0.1", 13, &$errno, &$errstr);
if (!$fp) {
echo "ERROR: $errno - $errstr<br>\n";
} else {
fwrite($fp,"\n");
echo fread($fp, 26);
fclose($fp);
}
?>
See also: pfsockopen()
Under the description, it says UDP is an option. also, an example is shown using the daytime protocol on port 13.
Another important question...
When I don't set non-blocking and try to read from a socket, if the server does not output an initial message, my fread or fgets freezes (possibly waiting for the input). BUT: if I use non-blocking, then the fread does not freeze, instead it does not read anything at all. I know there is nothing to read on port 80. but i'm writing a port scanner and it treats every port as if it doesn't know what to expect. So when I set non-blocking and if the program comes to lets say... port 13, it does not read anything (the datestamp); but it reads it if I remove the non-blocking and set it to blocking mode.
Is this a bug? or am I doing something wrong?
Would you be able to suggest how I may over-come this? I was thinking of doing a "timeout" read... Is there such a thing?
thanks for all your help,
Sridhar
