perl function getpeername

The getpeername function in Perl is used to retrieve the address of the peer to which a socket is connected.

Here's an example of using getpeername in Perl:

#!/usr/bin/perl

use strict;
use warnings;
use IO::Socket;

# Create a new socket
my $socket = IO::Socket::INET->new(
    PeerAddr => "example.com",
    PeerPort => "http(80)",
    Proto    => "tcp"
);

if (!$socket) {
    die "Could not create socket: $!\n";
}

# Get the peer address and port
my $peer_addr = getpeername($socket);
my ($peer_port, $peer_ip) = sockaddr_in($peer_addr);

# Convert the IP address to dotted-quad string format
my $peer_ip_str = inet_ntoa($peer_ip);

print "Connected to $peer_ip_str:$peer_port\n";

# Close the socket
close($socket);

In this example, we create a new TCP socket and connect to the HTTP service on "example.com". We then use the getpeername function to retrieve the address of the peer to which the socket is connected. This address is returned in binary format, so we use the sockaddr_in function from the Socket module to extract the peer port and IP address.

We then convert the IP address to a dotted-quad string format using the inet_ntoa function, and print the resulting string to the console.

Finally, we close the socket using the close function.

When you run this script, it will print the IP address and port number of the peer to which the socket is connected, assuming that the connection is successful.

Note that the specific behavior of getpeername may depend on the type of socket and the network protocol being used, and that it may be necessary to have appropriate privileges to access socket information. Additionally, the socket must be connected before getpeername can be called.