Question

I’m trying to create a chat server using sockets in Perl. However, when I run the Server program I get the error:

“ERROR:(9)(Bad file descriptor)(6)(+The handle is invalid) at Server.pl line 21.”

and when I run the client program I get the error:

“Cannot create the socket: No connection could be made because the target machine
actively refused it.”

Here is the Server program:

#!usr/bin/perl
#server.pl

use IO::Socket;
$| = 1;

print "Server Program\n";
my $lp = 12000;

my $server_socket, $new_client, $addr, $port;

$server_socket = new IO::Socket::INET (
LocalHost => '127.0.0.1',
LocalPort => $lp,
Proto => 'tcp',
Reuse => 1) or die "Cannot create the socket: $!\n";

print "Server started at port $lp \n";

while (1) {
    $new_client = $server_socket->accept() or die sprintf "ERROR:(%d)(%s)(%d)(+%s)", $!,$!,$^E,$^E;

$addr = $new_client->peerhost();
$port = $new_client->peerport();
print "Connected to client at $addr at port $port ";
while(<$new_client>) {
    print "Following is the text entered by client: \n";
    print "$_";
}
print "Client now disconnecting..\n";
close $new_client;
}

$server_socker->close();

And here is the client:

#!usr/bin/perl
#client.pl

use IO::Socket;
$| = 1;

print "Client Program\n";

my $lp = 12000;

my $client_socket = new IO::Socket::INET (
PeerHost => '127.0.0.1',
PeerPort => $lp,
Proto => 'tcp',
Reuse => 1) or die "Cannot create the socket: $!\n";

print "Server connected at port $lp \n";
print "Enter the text to sent to the server: \n";
$user_input = <>;
chomp $user_input;
print $plient_socket;
$client_socket->send($user_input);
$client_socket->close();

I am new to this and I’m not getting where I’m going wrong. Could anybody help?

Answer 1

You trying to accept a connection from a socket that’s not listening. Add

Listen => SOMAXCONN,

---

And now for off-topic comments about your code:

• Always use use strict; use warnings;. It will highlight some other problems with your code.

• It doesn’t make any sense to relative paths on the shebang line. You’re missing a /.

• On the style front, it’s considered bad form to declare variables ahead of where they are used. The whole point of declaring variables is to limit their scope, so declaring them at the top of the program defies the purpose.

• LocalHost => '127.0.0.1' (better written as LocalHost => INADDR_LOOPBACK) makes it so you can only receive connections from 127.0.0.1. That can be useful, but I don’t know if you did that intentionally. The default, INADDR_ANY, allows connections from any interface.