package Net::Ping;
-# Current maintainer: colinm@cpan.org (Colin McMillen)
-#
-# Original author: mose@ccsn.edu (Russell Mosemann)
-#
-# Authors of the original pingecho():
-# karrer@bernina.ethz.ch (Andreas Karrer)
-# Paul.Marquess@btinternet.com (Paul Marquess)
-#
-# Copyright (c) 2001, Colin McMillen. All rights reserved. This
-# program is free software; you may redistribute it and/or modify it
-# under the same terms as Perl itself.
-use 5.005_64;
+# $Id: Ping.pm,v 1.13 2001/12/07 02:18:44 rob Exp $
+
+require 5.002;
require Exporter;
use strict;
-our(@ISA, @EXPORT, $VERSION, $def_timeout, $def_proto, $max_datasize);
+use vars qw(@ISA @EXPORT $VERSION
+ $def_timeout $def_proto $max_datasize $pingstring);
use FileHandle;
use Socket qw( SOCK_DGRAM SOCK_STREAM SOCK_RAW PF_INET
- inet_aton inet_ntoa sockaddr_in );
+ inet_aton sockaddr_in );
use Carp;
@ISA = qw(Exporter);
@EXPORT = qw(pingecho);
-$VERSION = 2.03;
+$VERSION = 2.09;
# Constants
$def_timeout = 5; # Default timeout to wait for a reply
$def_proto = "udp"; # Default protocol to use for pinging
$max_datasize = 1024; # Maximum data bytes in a packet
+# The data we exchange with the server for the stream protocol
+$pingstring = "pingschwingping!\n";
# Description: The pingecho() subroutine is provided for backward
# compatibility with the original Net::Ping. It accepts a host
bless($self, $class);
$proto = $def_proto unless $proto; # Determine the protocol
- croak('Protocol for ping must be "icmp", "tcp", "udp", or "external"')
- unless $proto =~ m/^(tcp|udp|icmp|external)$/;
+ croak('Protocol for ping must be "icmp", "udp", "tcp", "stream", or "external"')
+ unless $proto =~ m/^(icmp|udp|tcp|stream|external)$/;
$self->{"proto"} = $proto;
$timeout = $def_timeout unless $timeout; # Determine the timeout
socket($self->{"fh"}, &PF_INET(), &SOCK_RAW(), $self->{"proto_num"}) ||
croak("icmp socket error - $!");
}
- elsif ($self->{"proto"} eq "tcp") # Just a file handle for now
+ elsif ($self->{"proto"} eq "tcp" || $self->{"proto"} eq "stream")
{
$self->{"proto_num"} = (getprotobyname('tcp'))[2] ||
croak("Can't get tcp protocol by name");
# Description: Ping a host name or IP number with an optional timeout.
# First lookup the host, and return undef if it is not found. Otherwise
-# perform the specific ping method based on the protocol. Return the
+# perform the specific ping method based on the protocol. Return the
# result of the ping.
sub ping
return $self->ping_udp($ip, $timeout) if $self->{"proto"} eq "udp";
return $self->ping_icmp($ip, $timeout) if $self->{"proto"} eq "icmp";
return $self->ping_tcp($ip, $timeout) if $self->{"proto"} eq "tcp";
+ return $self->ping_stream($ip, $timeout) if $self->{"proto"} eq "stream";
croak("Unknown protocol \"$self->{proto}\" in ping()");
}
$timeout # Seconds after which ping times out
) = @_;
- eval { require Net::Ping::External; };
- croak('Protocol "external" not supported on your system: Net::Ping::External not found') if $@;
+ eval { require Net::Ping::External; }
+ or croak('Protocol "external" not supported on your system: Net::Ping::External not found');
return Net::Ping::External::ping(ip => $ip, timeout => $timeout);
}
return(~(($chk >> 16) + $chk) & 0xffff); # Again and complement
}
+
# Description: Perform a tcp echo ping. Since a tcp connection is
# host specific, we have to open and close each connection here. We
# can't just leave a socket open. Because of the robust nature of
# tcp, it will take a while before it gives up trying to establish a
# connection. Therefore, we use select() on a non-blocking socket to
-# check against our timeout. No data bytes are actually
+# check against our timeout. No data bytes are actually
# sent since the successful establishment of a connection is proof
# enough of the reachability of the remote host. Also, tcp is
# expensive and doesn't need our help to add to the overhead.
sub ping_tcp
{
- my ($self,
- $ip, # Packed IP number of the host
- $timeout # Seconds after which ping times out
- ) = @_;
- my ($saddr, # sockaddr_in with port and ip
- $rin, # Used in select()
- $ret # The return value
- );
+ my ($self,
+ $ip, # Packed IP number of the host
+ $timeout # Seconds after which ping times out
+ ) = @_;
+ my ($ret # The return value
+ );
- socket($self->{"fh"}, &PF_INET(), &SOCK_STREAM(), $self->{"proto_num"}) ||
- croak("tcp socket error - $!");
+ $@ = "";
+ $ret = $self -> tcp_connect( $ip, $timeout);
+ $ret = 1 if $@ =~ /(Connection Refused|Unknown Error)/i;
+ $self->{"fh"}->close();
+ return($ret);
+}
- $saddr = sockaddr_in($self->{"port_num"}, $ip);
+sub tcp_connect
+{
+ my ($self,
+ $ip, # Packed IP number of the host
+ $timeout # Seconds after which connect times out
+ ) = @_;
+ my ($saddr); # Packed IP and Port
- $ret = 0; # Default to unreachable
+ $saddr = sockaddr_in($self->{"port_num"}, $ip);
- # Buggy Winsock API doesn't allow us to use non-blocking connect()
- # calls. Hence, if our OS is Windows, we need to create a new process
- # to run a blocking connect attempt, and kill it after the timeout has
- # passed.
- if ($^O =~ /win32/i)
- {
- my ($child, $ret, $pid, $time);
- my $host = inet_ntoa($ip);
+ my $ret = 0; # Default to unreachable
- # The code we will be executing in our new process.
- my $code = '"use Net::Ping; $p = Net::Ping->new(\'tcp\'); ';
- $code .= 'exit($p->_ping_tcp_win(' . $host . '))"';
+ my $do_socket = sub {
+ socket($self->{"fh"}, &PF_INET(), &SOCK_STREAM(), $self->{"proto_num"}) ||
+ croak("tcp socket error - $!");
+ };
+ my $do_connect = sub {
+ eval {
+ die $! unless connect($self->{"fh"}, $saddr);
+ $self->{"ip"} = $ip;
+ $ret = 1;
+ };
+ $ret;
+ };
+
+ if ($^O =~ /Win32/i) {
+
+ # Buggy Winsock API doesn't allow us to use alarm() calls.
+ # Hence, if our OS is Windows, we need to create a separate
+ # process to do the blocking connect attempt.
+
+ $| = 1; # Clear buffer prior to fork to prevent duplicate flushing.
+ my $pid = fork;
+ if (!$pid) {
+ if (!defined $pid) {
+ # Fork did not work
+ warn "Win32 Fork error: $!";
+ return 0;
+ }
+ &{ $do_socket }();
+
+ # Try a slow blocking connect() call
+ # and report the status to the pipe.
+ if ( &{ $do_connect }() ) {
+ $self->{"fh"}->close();
+ # No error
+ exit 0;
+ } else {
+ # Pass the error status to the parent
+ exit $!;
+ }
+ }
- # Call the process.
- $pid = system(1, "perl", "-e", $code);
+ &{ $do_socket }();
+
+ my $patience = time + $timeout;
- # Import the POSIX version of <sys/wait.h>
require POSIX;
- import POSIX qw(:sys_wait_h);
+ my ($child);
+ $? = 0;
+ # Wait up to the timeout
+ # And clean off the zombie
+ do {
+ $child = waitpid($pid, &POSIX::WNOHANG);
+ $! = $? >> 8;
+ $@ = $!;
+ select(undef, undef, undef, 0.1);
+ } while time < $patience && $child != $pid;
+
+ if ($child == $pid) {
+ # Since she finished within the timeout,
+ # it is probably safe for me to try it too
+ &{ $do_connect }();
+ } else {
+ # Time must have run out.
+ $@ = "Timed out!";
+ # Put that choking client out of its misery
+ kill "KILL", $pid;
+ # Clean off the zombie
+ waitpid($pid, 0);
+ $ret = 0;
+ }
+ } else { # Win32
+ # Otherwise don't waste the resources to fork
+
+ &{ $do_socket }();
+
+ $SIG{'ALRM'} = sub { die "Timed out!"; };
+ alarm($timeout); # Interrupt connect() if we have to
+
+ &{ $do_connect }();
+ alarm(0);
+ }
- # Get the current time; will be used to tell if we've timed out.
- $time = time;
+ return $ret;
+}
- # Wait for the child to return or for the timeout to expire.
- do {
- $child = waitpid($pid, &WNOHANG);
- $ret = $?;
- } until time > ($time + $timeout) or $child;
-
- # Return an appropriate value; 0 if the child didn't return,
- # the return value of the child otherwise.
- return $ret >> 8 if $child;
-
- kill $pid;
- return 0;
- }
-
- # If our OS isn't Windows, do this stuff instead...
- else
- {
- # Try a non-blocking TCP connect to the remote echo port.
- # Our call to select() below will stop after the timeout has
- # passed or set the return value to true if the connection
- # succeeds in time.
- $self->{"fh"}->blocking(0);
- connect($self->{"fh"}, $saddr);
-
- $rin = "";
- vec($rin, fileno($self->{"fh"}), 1) = 1;
- $ret = 1 if select($rin, undef, undef, $timeout);
-
- # Close our filehandle, restore it to its default state (i.e. blocking),
- # and return our result.
- $self->{"fh"}->blocking(1);
- $self->{"fh"}->close();
- }
- return($ret);
+# This writes the given string to the socket and then reads it
+# back. It returns 1 on success, 0 on failure.
+sub tcp_echo
+{
+ my $self = shift;
+ my $timeout = shift;
+ my $pingstring = shift;
+
+ my $ret = undef;
+ my $time = time;
+ my $wrstr = $pingstring;
+ my $rdstr = "";
+
+ eval <<'EOM';
+ do {
+ my $rin = "";
+ vec($rin, $self->{"fh"}->fileno(), 1) = 1;
+
+ my $rout = undef;
+ if($wrstr) {
+ $rout = "";
+ vec($rout, $self->{"fh"}->fileno(), 1) = 1;
+ }
+
+ if(select($rin, $rout, undef, ($time + $timeout) - time())) {
+
+ if($rout && vec($rout,$self->{"fh"}->fileno(),1)) {
+ my $num = syswrite($self->{"fh"}, $wrstr);
+ if($num) {
+ # If it was a partial write, update and try again.
+ $wrstr = substr($wrstr,$num);
+ } else {
+ # There was an error.
+ $ret = 0;
+ }
+ }
+
+ if(vec($rin,$self->{"fh"}->fileno(),1)) {
+ my $reply;
+ if(sysread($self->{"fh"},$reply,length($pingstring)-length($rdstr))) {
+ $rdstr .= $reply;
+ $ret = 1 if $rdstr eq $pingstring;
+ } else {
+ # There was an error.
+ $ret = 0;
+ }
+ }
+
+ }
+ } until time() > ($time + $timeout) || defined($ret);
+EOM
+
+ return $ret;
}
-# Warning: this method may generate false positives.
-# It is meant to be a private method and should only
-# be invoked by ping_tcp() if $^O =~ /win32/i.
-sub _ping_tcp_win
+
+
+
+# Description: Perform a stream ping. If the tcp connection isn't
+# already open, it opens it. It then sends some data and waits for
+# a reply. It leaves the stream open on exit.
+
+sub ping_stream
{
my ($self,
$ip, # Packed IP number of the host
+ $timeout # Seconds after which ping times out
) = @_;
- my ($saddr, # sockaddr_in with port and ip
- $ret # The return value
- );
- socket($self->{"fh"}, &PF_INET(), &SOCK_STREAM(), $self->{"proto_num"}) ||
- croak("tcp socket error - $!");
+ # Open the stream if it's not already open
+ if(!defined $self->{"fh"}->fileno()) {
+ $self->tcp_connect($ip, $timeout) or return 0;
+ }
- $saddr = sockaddr_in($self->{"port_num"}, $ip);
+ croak "tried to switch servers while stream pinging"
+ if $self->{"ip"} ne $ip;
- $ret = 0; # Default to unreachable
+ return $self->tcp_echo($timeout, $pingstring);
+}
+
+# Description: opens the stream. You would do this if you want to
+# separate the overhead of opening the stream from the first ping.
- eval { $ret = connect($self->{"fh"}, $saddr) };
+sub open
+{
+ my ($self,
+ $host, # Host or IP address
+ $timeout # Seconds after which open times out
+ ) = @_;
- # If the remote host exists but returns "Connection refused",
- # the call to connect() sets $! to "Unknown error". So, we
- # assume that an "Unknown error" actually means the host is
- # alive. This assumption may occassionally give false positives.
- $ret = 1 if $! =~ /Unknown error/i;
+ my ($ip); # Packed IP number of the host
+ $ip = inet_aton($host);
+ $timeout = $self->{"timeout"} unless $timeout;
- $self->{"fh"}->close();
- return $ret;
+ if($self->{"proto"} eq "stream") {
+ if(defined($self->{"fh"}->fileno())) {
+ croak("socket is already open");
+ } else {
+ $self->tcp_connect($ip, $timeout);
+ }
+ }
}
+
# Description: Perform a udp echo ping. Construct a message of
# at least the one-byte sequence number and any additional data bytes.
# Send the message out and wait for a message to come back. If we
}
}
return($ret);
-}
+}
# Description: Close the connection unless we are using the tcp
# protocol, since it will already be closed.
Net::Ping - check a remote host for reachability
+$Id: Ping.pm,v 1.13 2001/12/07 02:18:44 rob Exp $
+
=head1 SYNOPSIS
use Net::Ping;
sleep(1);
}
$p->close();
-
+
$p = Net::Ping->new("tcp", 2);
+ # Try connecting to the www port instead of the echo port
+ $p->{port_num} = getservbyname("http", "tcp");
while ($stop_time > time())
{
print "$host not reachable ", scalar(localtime()), "\n"
sleep(300);
}
undef($p);
-
+
# For backward compatibility
print "$host is alive.\n" if pingecho($host);
received from the remote host and the received packet contains the
same data as the packet that was sent, the remote host is considered
reachable. This protocol does not require any special privileges.
-
-It should be borne in mind that, for both udp ping, a host
+It should be borne in mind that, for a udp ping, a host
will be reported as unreachable if it is not running the
-appropriate echo service. For Unix-like systems see L<inetd(8)> for
-more information.
+appropriate echo service. For Unix-like systems see L<inetd(8)>
+for more information.
If the "icmp" protocol is specified, the ping() method sends an icmp
echo message to the remote host, which is what the UNIX ping program
1 is returned if the host is reachable and 0 if it is not. For all
practical purposes, undef and 0 and can be treated as the same case.
+=item $p->open($host);
+
+When you are using the stream protocol, this call pre-opens the
+tcp socket. It's only necessary to do this if you want to
+provide a different timeout when creating the connection, or
+remove the overhead of establishing the connection from the
+first ping. If you don't call C<open()>, the connection is
+automatically opened the first time C<ping()> is called.
+This call simply does nothing if you are using any protocol other
+than stream.
+
+=item $p->open($host);
+
+When you are using the stream protocol, this call pre-opens the
+tcp socket. It's only necessary to do this if you want to
+provide a different timeout when creating the connection, or
+remove the overhead of establishing the connection from the
+first ping. If you don't call C<open()>, the connection is
+automatically opened the first time C<ping()> is called.
+This call simply does nothing if you are using any protocol other
+than stream.
+
=item $p->close();
Close the network connection for this ping object. The network
=back
+=head1 WARNING
+
+pingecho() or a ping object with the tcp protocol use alarm() to
+implement the timeout. So, don't use alarm() in your program while
+you are using pingecho() or a ping object with the tcp protocol. The
+udp and icmp protocols do not use alarm() to implement the timeout.
+
=head1 NOTES
There will be less network overhead (and some efficiency in your
avoid flooding your network with packets.
The icmp protocol requires that the program be run as root or that it
-be setuid to root. The tcp and udp protocols do not require special
-privileges, but not all network devices implement the echo protocol
-for tcp or udp.
+be setuid to root. The other protocols do not require special
+privileges, but not all network devices implement tcp or udp echo.
Local hosts should normally respond to pings within milliseconds.
However, on a very congested network it may take up to 3 seconds or
host is not reachable (which is almost the truth).
Reachability doesn't necessarily mean that the remote host is actually
-functioning beyond its ability to echo packets.
+functioning beyond its ability to echo packets. tcp is slightly better
+at indicating the health of a system than icmp because it uses more
+of the networking stack to respond.
Because of a lack of anything better, this module uses its own
routines to pack and unpack ICMP packets. It would be better for a
separate module to be written which understands all of the different
kinds of ICMP packets.
+=head1 AUTHOR(S)
+
+ Current maintainer Net::Ping base code:
+ colinm@cpan.org (Colin McMillen)
+
+ Stream protocol:
+ bronson@trestle.com (Scott Bronson)
+
+ Original pingecho():
+ karrer@bernina.ethz.ch (Andreas Karrer)
+ pmarquess@bfsec.bt.co.uk (Paul Marquess)
+
+ Original Net::Ping author:
+ mose@ns.ccsn.edu (Russell Mosemann)
+
+ Compatibility porting:
+ bbb@cpan.org (Rob Brown)
+
+=head1 COPYRIGHT
+
+Copyright (c) 2001, Colin McMillen. All rights reserved.
+Copyright (c) 2001, Rob Brown. All rights reserved.
+
+This program is free software; you may redistribute it and/or
+modify it under the same terms as Perl itself.
+
=cut
projects / p5sagit/p5-mst-13.2.git / blobdiff