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package Net::Ping;
# Authors: karrer@bernina.ethz.ch (Andreas Karrer)
# pmarquess@bfsec.bt.co.uk (Paul Marquess)
require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(ping pingecho);
use Socket;
use Carp ;
$tcp_proto = (getprotobyname('tcp'))[2];
$echo_port = (getservbyname('echo', 'tcp'))[2];
sub ping {
croak "ping not implemented yet. Use pingecho()";
}
sub pingecho {
croak "usage: pingecho host [timeout]"
unless @_ == 1 || @_ == 2 ;
local ($host, $timeout) = @_;
local (*PINGSOCK);
local ($saddr, $ip);
local ($ret) ;
# check if $host is alive by connecting to its echo port, within $timeout
# (default 5) seconds. returns 1 if OK, 0 if no answer, 0 if host not found
$timeout = 5 unless $timeout;
if ($host =~ /^\s*((\d+\.){3}\d+)\s*$/)
{ $ip = pack ('C4', split (/\./, $1)) }
else
{ $ip = (gethostbyname($host))[4] }
return 0 unless $ip; # "no such host"
$saddr = pack('S n a4 x8', AF_INET, $echo_port, $ip);
$SIG{'ALRM'} = sub { die } ;
alarm($timeout);
$ret = eval <<'EOM' ;
return 0
unless socket(PINGSOCK, PF_INET, SOCK_STREAM, $tcp_proto) ;
return 0
unless connect(PINGSOCK, $saddr) ;
return 1 ;
EOM
alarm(0);
close(PINGSOCK);
$ret == 1 ? 1 : 0 ;
}
1;
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