package Net::Ping;
-# 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) 1996 Russell Mosemann. 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 1.33 2002/10/19 05:02:43 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 $hires $source_verify $syn_forking);
+use Fcntl qw( F_GETFL F_SETFL O_NONBLOCK );
+use Socket qw( SOCK_DGRAM SOCK_STREAM SOCK_RAW PF_INET SOL_SOCKET
+ inet_aton inet_ntoa sockaddr_in );
+use POSIX qw( ECONNREFUSED EINPROGRESS WNOHANG );
use FileHandle;
-use Socket qw( SOCK_DGRAM SOCK_STREAM SOCK_RAW PF_INET
- inet_aton sockaddr_in );
use Carp;
@ISA = qw(Exporter);
@EXPORT = qw(pingecho);
-$VERSION = 2.02;
+$VERSION = "2.23";
# Constants
$def_timeout = 5; # Default timeout to wait for a reply
-$def_proto = "udp"; # Default protocol to use for pinging
+$def_proto = "tcp"; # 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";
+$source_verify = 1; # Default is to verify source endpoint
+$syn_forking = 0;
+
+if ($^O =~ /Win32/i) {
+ # Hack to avoid this Win32 spewage:
+ # Your vendor has not defined POSIX macro ECONNREFUSED
+ *ECONNREFUSED = sub {10061;}; # "Unknown Error" Special Win32 Response?
+ $syn_forking = 1;
+};
+
+# h2ph "asm/socket.h"
+# require "asm/socket.ph";
+sub SO_BINDTODEVICE {25;}
# Description: The pingecho() subroutine is provided for backward
# compatibility with the original Net::Ping. It accepts a host
sub pingecho
{
- my ($host, # Name or IP number of host to ping
- $timeout # Optional timeout in seconds
- ) = @_;
- my ($p); # A ping object
+ my ($host, # Name or IP number of host to ping
+ $timeout # Optional timeout in seconds
+ ) = @_;
+ my ($p); # A ping object
- $p = Net::Ping->new("tcp", $timeout);
- $p->ping($host); # Going out of scope closes the connection
+ $p = Net::Ping->new("tcp", $timeout);
+ $p->ping($host); # Going out of scope closes the connection
}
# Description: The new() method creates a new ping object. Optional
sub new
{
- my ($this,
- $proto, # Optional protocol to use for pinging
- $timeout, # Optional timeout in seconds
- $data_size # Optional additional bytes of data
- ) = @_;
- my $class = ref($this) || $this;
- my $self = {};
- my ($cnt, # Count through data bytes
- $min_datasize # Minimum data bytes required
- );
-
- bless($self, $class);
-
- $proto = $def_proto unless $proto; # Determine the protocol
- croak("Protocol for ping must be \"tcp\", \"udp\" or \"icmp\"")
- unless $proto =~ m/^(tcp|udp|icmp)$/;
- $self->{"proto"} = $proto;
-
- $timeout = $def_timeout unless $timeout; # Determine the timeout
- croak("Default timeout for ping must be greater than 0 seconds")
- if $timeout <= 0;
- $self->{"timeout"} = $timeout;
-
- $min_datasize = ($proto eq "udp") ? 1 : 0; # Determine data size
- $data_size = $min_datasize unless defined($data_size) && $proto ne "tcp";
- croak("Data for ping must be from $min_datasize to $max_datasize bytes")
- if ($data_size < $min_datasize) || ($data_size > $max_datasize);
- $data_size-- if $self->{"proto"} eq "udp"; # We provide the first byte
- $self->{"data_size"} = $data_size;
-
- $self->{"data"} = ""; # Construct data bytes
- for ($cnt = 0; $cnt < $self->{"data_size"}; $cnt++)
- {
- $self->{"data"} .= chr($cnt % 256);
- }
-
- $self->{"seq"} = 0; # For counting packets
- if ($self->{"proto"} eq "udp") # Open a socket
- {
- $self->{"proto_num"} = (getprotobyname('udp'))[2] ||
- croak("Can't udp protocol by name");
- $self->{"port_num"} = (getservbyname('echo', 'udp'))[2] ||
- croak("Can't get udp echo port by name");
- $self->{"fh"} = FileHandle->new();
- socket($self->{"fh"}, &PF_INET(), &SOCK_DGRAM(),
- $self->{"proto_num"}) ||
- croak("udp socket error - $!");
+ my ($this,
+ $proto, # Optional protocol to use for pinging
+ $timeout, # Optional timeout in seconds
+ $data_size, # Optional additional bytes of data
+ $device, # Optional device to use
+ ) = @_;
+ my $class = ref($this) || $this;
+ my $self = {};
+ my ($cnt, # Count through data bytes
+ $min_datasize # Minimum data bytes required
+ );
+
+ bless($self, $class);
+
+ $proto = $def_proto unless $proto; # Determine the protocol
+ croak('Protocol for ping must be "icmp", "udp", "tcp", "syn", "stream", or "external"')
+ unless $proto =~ m/^(icmp|udp|tcp|syn|stream|external)$/;
+ $self->{"proto"} = $proto;
+
+ $timeout = $def_timeout unless $timeout; # Determine the timeout
+ croak("Default timeout for ping must be greater than 0 seconds")
+ if $timeout <= 0;
+ $self->{"timeout"} = $timeout;
+
+ $self->{"device"} = $device;
+
+ $min_datasize = ($proto eq "udp") ? 1 : 0; # Determine data size
+ $data_size = $min_datasize unless defined($data_size) && $proto ne "tcp";
+ croak("Data for ping must be from $min_datasize to $max_datasize bytes")
+ if ($data_size < $min_datasize) || ($data_size > $max_datasize);
+ $data_size-- if $self->{"proto"} eq "udp"; # We provide the first byte
+ $self->{"data_size"} = $data_size;
+
+ $self->{"data"} = ""; # Construct data bytes
+ for ($cnt = 0; $cnt < $self->{"data_size"}; $cnt++)
+ {
+ $self->{"data"} .= chr($cnt % 256);
+ }
+
+ $self->{"local_addr"} = undef; # Don't bind by default
+
+ $self->{"tcp_econnrefused"} = undef; # Default Connection refused behavior
+
+ $self->{"seq"} = 0; # For counting packets
+ if ($self->{"proto"} eq "udp") # Open a socket
+ {
+ $self->{"proto_num"} = (getprotobyname('udp'))[2] ||
+ croak("Can't udp protocol by name");
+ $self->{"port_num"} = (getservbyname('echo', 'udp'))[2] ||
+ croak("Can't get udp echo port by name");
+ $self->{"fh"} = FileHandle->new();
+ socket($self->{"fh"}, PF_INET, SOCK_DGRAM,
+ $self->{"proto_num"}) ||
+ croak("udp socket error - $!");
+ if ($self->{'device'}) {
+ setsockopt($self->{"fh"}, SOL_SOCKET, SO_BINDTODEVICE(), pack("Z*", $self->{'device'}))
+ or croak "error binding to device $self->{'device'} $!";
}
- elsif ($self->{"proto"} eq "icmp")
- {
- croak("icmp ping requires root privilege") if ($> and $^O ne 'VMS');
- $self->{"proto_num"} = (getprotobyname('icmp'))[2] ||
- croak("Can't get icmp protocol by name");
- $self->{"pid"} = $$ & 0xffff; # Save lower 16 bits of pid
- $self->{"fh"} = FileHandle->new();
- socket($self->{"fh"}, &PF_INET(), &SOCK_RAW(), $self->{"proto_num"}) ||
- croak("icmp socket error - $!");
+ }
+ elsif ($self->{"proto"} eq "icmp")
+ {
+ croak("icmp ping requires root privilege") if ($> and $^O ne 'VMS' and $^O ne 'cygwin');
+ $self->{"proto_num"} = (getprotobyname('icmp'))[2] ||
+ croak("Can't get icmp protocol by name");
+ $self->{"pid"} = $$ & 0xffff; # Save lower 16 bits of pid
+ $self->{"fh"} = FileHandle->new();
+ socket($self->{"fh"}, PF_INET, SOCK_RAW, $self->{"proto_num"}) ||
+ croak("icmp socket error - $!");
+ if ($self->{'device'}) {
+ setsockopt($self->{"fh"}, SOL_SOCKET, SO_BINDTODEVICE(), pack("Z*", $self->{'device'}))
+ or croak "error binding to device $self->{'device'} $!";
}
- elsif ($self->{"proto"} eq "tcp") # Just a file handle for now
- {
- $self->{"proto_num"} = (getprotobyname('tcp'))[2] ||
- croak("Can't get tcp protocol by name");
- $self->{"port_num"} = (getservbyname('echo', 'tcp'))[2] ||
- croak("Can't get tcp echo port by name");
- $self->{"fh"} = FileHandle->new();
+ }
+ elsif ($self->{"proto"} eq "tcp" || $self->{"proto"} eq "stream")
+ {
+ $self->{"proto_num"} = (getprotobyname('tcp'))[2] ||
+ croak("Can't get tcp protocol by name");
+ $self->{"port_num"} = (getservbyname('echo', 'tcp'))[2] ||
+ croak("Can't get tcp echo port by name");
+ $self->{"fh"} = FileHandle->new();
+ }
+ elsif ($self->{"proto"} eq "syn")
+ {
+ $self->{"proto_num"} = (getprotobyname('tcp'))[2] ||
+ croak("Can't get tcp protocol by name");
+ $self->{"port_num"} = (getservbyname('echo', 'tcp'))[2] ||
+ croak("Can't get tcp echo port by name");
+ if ($syn_forking) {
+ $self->{"fork_rd"} = FileHandle->new();
+ $self->{"fork_wr"} = FileHandle->new();
+ pipe($self->{"fork_rd"}, $self->{"fork_wr"});
+ $self->{"fh"} = FileHandle->new();
+ } else {
+ $self->{"wbits"} = "";
+ $self->{"bad"} = {};
}
+ $self->{"syn"} = {};
+ $self->{"stop_time"} = 0;
+ }
+ elsif ($self->{"proto"} eq "external")
+ {
+ # No preliminary work needs to be done.
+ }
+
+ return($self);
+}
+
+# Description: Set the local IP address from which pings will be sent.
+# For ICMP and UDP pings, this calls bind() on the already-opened socket;
+# for TCP pings, just saves the address to be used when the socket is
+# opened. Returns non-zero if successful; croaks on error.
+sub bind
+{
+ my ($self,
+ $local_addr # Name or IP number of local interface
+ ) = @_;
+ my ($ip # Packed IP number of $local_addr
+ );
+
+ croak("Usage: \$p->bind(\$local_addr)") unless @_ == 2;
+ croak("already bound") if defined($self->{"local_addr"}) &&
+ ($self->{"proto"} eq "udp" || $self->{"proto"} eq "icmp");
+
+ $ip = inet_aton($local_addr);
+ croak("nonexistent local address $local_addr") unless defined($ip);
+ $self->{"local_addr"} = $ip; # Only used if proto is tcp
+
+ if ($self->{"proto"} eq "udp" || $self->{"proto"} eq "icmp")
+ {
+ CORE::bind($self->{"fh"}, sockaddr_in(0, $ip)) ||
+ croak("$self->{'proto'} bind error - $!");
+ }
+ elsif ($self->{"proto"} ne "tcp")
+ {
+ croak("Unknown protocol \"$self->{proto}\" in bind()");
+ }
+
+ return 1;
+}
+
+
+# Description: Allow UDP source endpoint comparision to be
+# skipped for those remote interfaces that do
+# not response from the same endpoint.
+
+sub source_verify
+{
+ my $self = shift;
+ $source_verify = 1 unless defined
+ ($source_verify = ((defined $self) && (ref $self)) ? shift() : $self);
+}
+
+# Description: Set whether or not the tcp connect
+# behavior should enforce remote service availability
+# as well as reachability.
+
+sub tcp_service_check
+{
+ my $self = shift;
+ $self->{"tcp_econnrefused"} = 1 unless defined
+ ($self->{"tcp_econnrefused"} = shift());
+}
+# Description: allows the module to use milliseconds as returned by
+# the Time::HiRes module
- return($self);
+$hires = 0;
+sub hires
+{
+ my $self = shift;
+ $hires = 1 unless defined
+ ($hires = ((defined $self) && (ref $self)) ? shift() : $self);
+ require Time::HiRes if $hires;
+}
+
+sub time
+{
+ return $hires ? Time::HiRes::time() : CORE::time();
}
# Description: Ping a host name or IP number with an optional timeout.
# First lookup the host, and return undef if it is not found. Otherwise
-# perform the specific ping method based on the protocol. Return the
+# perform the specific ping method based on the protocol. Return the
# result of the ping.
sub ping
{
- my ($self,
- $host, # Name or IP number of host to ping
- $timeout # Seconds after which ping times out
- ) = @_;
- my ($ip, # Packed IP number of $host
- $ret # The return value
- );
-
- croak("Usage: \$p->ping(\$host [, \$timeout])") unless @_ == 2 || @_ == 3;
- $timeout = $self->{"timeout"} unless $timeout;
- croak("Timeout must be greater than 0 seconds") if $timeout <= 0;
-
- $ip = inet_aton($host);
- return(undef) unless defined($ip); # Does host exist?
-
- if ($self->{"proto"} eq "udp")
- {
- $ret = $self->ping_udp($ip, $timeout);
- }
- elsif ($self->{"proto"} eq "icmp")
- {
- $ret = $self->ping_icmp($ip, $timeout);
- }
- elsif ($self->{"proto"} eq "tcp")
- {
- $ret = $self->ping_tcp($ip, $timeout);
- }
- else
- {
- croak("Unknown protocol \"$self->{proto}\" in ping()");
- }
- return($ret);
+ my ($self,
+ $host, # Name or IP number of host to ping
+ $timeout, # Seconds after which ping times out
+ ) = @_;
+ my ($ip, # Packed IP number of $host
+ $ret, # The return value
+ $ping_time, # When ping began
+ );
+
+ croak("Usage: \$p->ping(\$host [, \$timeout])") unless @_ == 2 || @_ == 3;
+ $timeout = $self->{"timeout"} unless $timeout;
+ croak("Timeout must be greater than 0 seconds") if $timeout <= 0;
+
+ $ip = inet_aton($host);
+ return(undef) unless defined($ip); # Does host exist?
+
+ # Dispatch to the appropriate routine.
+ $ping_time = &time();
+ if ($self->{"proto"} eq "external") {
+ $ret = $self->ping_external($ip, $timeout);
+ }
+ elsif ($self->{"proto"} eq "udp") {
+ $ret = $self->ping_udp($ip, $timeout);
+ }
+ elsif ($self->{"proto"} eq "icmp") {
+ $ret = $self->ping_icmp($ip, $timeout);
+ }
+ elsif ($self->{"proto"} eq "tcp") {
+ $ret = $self->ping_tcp($ip, $timeout);
+ }
+ elsif ($self->{"proto"} eq "stream") {
+ $ret = $self->ping_stream($ip, $timeout);
+ }
+ elsif ($self->{"proto"} eq "syn") {
+ $ret = $self->ping_syn($host, $ip, $ping_time, $ping_time+$timeout);
+ } else {
+ croak("Unknown protocol \"$self->{proto}\" in ping()");
+ }
+
+ return wantarray ? ($ret, &time() - $ping_time, inet_ntoa($ip)) : $ret;
}
+# Uses Net::Ping::External to do an external ping.
+sub ping_external {
+ my ($self,
+ $ip, # Packed IP number of the host
+ $timeout # Seconds after which ping times out
+ ) = @_;
+
+ 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 => $timeout);
+}
+
+use constant ICMP_ECHOREPLY => 0; # ICMP packet types
+use constant ICMP_ECHO => 8;
+use constant ICMP_STRUCT => "C2 S3 A"; # Structure of a minimal ICMP packet
+use constant SUBCODE => 0; # No ICMP subcode for ECHO and ECHOREPLY
+use constant ICMP_FLAGS => 0; # No special flags for send or recv
+use constant ICMP_PORT => 0; # No port with ICMP
+
sub ping_icmp
{
- my ($self,
- $ip, # Packed IP number of the host
- $timeout # Seconds after which ping times out
- ) = @_;
-
- my $ICMP_ECHOREPLY = 0; # ICMP packet types
- my $ICMP_ECHO = 8;
- my $icmp_struct = "C2 S3 A"; # Structure of a minimal ICMP packet
- my $subcode = 0; # No ICMP subcode for ECHO and ECHOREPLY
- my $flags = 0; # No special flags when opening a socket
- my $port = 0; # No port with ICMP
-
- my ($saddr, # sockaddr_in with port and ip
- $checksum, # Checksum of ICMP packet
- $msg, # ICMP packet to send
- $len_msg, # Length of $msg
- $rbits, # Read bits, filehandles for reading
- $nfound, # Number of ready filehandles found
- $finish_time, # Time ping should be finished
- $done, # set to 1 when we are done
- $ret, # Return value
- $recv_msg, # Received message including IP header
- $from_saddr, # sockaddr_in of sender
- $from_port, # Port packet was sent from
- $from_ip, # Packed IP of sender
- $from_type, # ICMP type
- $from_subcode, # ICMP subcode
- $from_chk, # ICMP packet checksum
- $from_pid, # ICMP packet id
- $from_seq, # ICMP packet sequence
- $from_msg # ICMP message
- );
-
- $self->{"seq"} = ($self->{"seq"} + 1) % 65536; # Increment sequence
- $checksum = 0; # No checksum for starters
- $msg = pack($icmp_struct . $self->{"data_size"}, $ICMP_ECHO, $subcode,
- $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"});
- $checksum = Net::Ping->checksum($msg);
- $msg = pack($icmp_struct . $self->{"data_size"}, $ICMP_ECHO, $subcode,
- $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"});
- $len_msg = length($msg);
- $saddr = sockaddr_in($port, $ip);
- send($self->{"fh"}, $msg, $flags, $saddr); # Send the message
-
- $rbits = "";
- vec($rbits, $self->{"fh"}->fileno(), 1) = 1;
- $ret = 0;
- $done = 0;
- $finish_time = time() + $timeout; # Must be done by this time
- while (!$done && $timeout > 0) # Keep trying if we have time
+ my ($self,
+ $ip, # Packed IP number of the host
+ $timeout # Seconds after which ping times out
+ ) = @_;
+
+ my ($saddr, # sockaddr_in with port and ip
+ $checksum, # Checksum of ICMP packet
+ $msg, # ICMP packet to send
+ $len_msg, # Length of $msg
+ $rbits, # Read bits, filehandles for reading
+ $nfound, # Number of ready filehandles found
+ $finish_time, # Time ping should be finished
+ $done, # set to 1 when we are done
+ $ret, # Return value
+ $recv_msg, # Received message including IP header
+ $from_saddr, # sockaddr_in of sender
+ $from_port, # Port packet was sent from
+ $from_ip, # Packed IP of sender
+ $from_type, # ICMP type
+ $from_subcode, # ICMP subcode
+ $from_chk, # ICMP packet checksum
+ $from_pid, # ICMP packet id
+ $from_seq, # ICMP packet sequence
+ $from_msg # ICMP message
+ );
+
+ $self->{"seq"} = ($self->{"seq"} + 1) % 65536; # Increment sequence
+ $checksum = 0; # No checksum for starters
+ $msg = pack(ICMP_STRUCT . $self->{"data_size"}, ICMP_ECHO, SUBCODE,
+ $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"});
+ $checksum = Net::Ping->checksum($msg);
+ $msg = pack(ICMP_STRUCT . $self->{"data_size"}, ICMP_ECHO, SUBCODE,
+ $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"});
+ $len_msg = length($msg);
+ $saddr = sockaddr_in(ICMP_PORT, $ip);
+ send($self->{"fh"}, $msg, ICMP_FLAGS, $saddr); # Send the message
+
+ $rbits = "";
+ vec($rbits, $self->{"fh"}->fileno(), 1) = 1;
+ $ret = 0;
+ $done = 0;
+ $finish_time = &time() + $timeout; # Must be done by this time
+ while (!$done && $timeout > 0) # Keep trying if we have time
+ {
+ $nfound = select($rbits, undef, undef, $timeout); # Wait for packet
+ $timeout = $finish_time - &time(); # Get remaining time
+ if (!defined($nfound)) # Hmm, a strange error
{
- $nfound = select($rbits, undef, undef, $timeout); # Wait for packet
- $timeout = $finish_time - time(); # Get remaining time
- if (!defined($nfound)) # Hmm, a strange error
- {
- $ret = undef;
- $done = 1;
- }
- elsif ($nfound) # Got a packet from somewhere
- {
- $recv_msg = "";
- $from_saddr = recv($self->{"fh"}, $recv_msg, 1500, $flags);
- ($from_port, $from_ip) = sockaddr_in($from_saddr);
- ($from_type, $from_subcode, $from_chk,
- $from_pid, $from_seq, $from_msg) =
- unpack($icmp_struct . $self->{"data_size"},
- substr($recv_msg, length($recv_msg) - $len_msg,
- $len_msg));
- if (($from_type == $ICMP_ECHOREPLY) &&
- ($from_ip eq $ip) &&
- ($from_pid == $self->{"pid"}) && # Does the packet check out?
- ($from_seq == $self->{"seq"}))
- {
- $ret = 1; # It's a winner
- $done = 1;
- }
- }
- else # Oops, timed out
- {
- $done = 1;
- }
+ $ret = undef;
+ $done = 1;
+ }
+ elsif ($nfound) # Got a packet from somewhere
+ {
+ $recv_msg = "";
+ $from_saddr = recv($self->{"fh"}, $recv_msg, 1500, ICMP_FLAGS);
+ ($from_port, $from_ip) = sockaddr_in($from_saddr);
+ ($from_type, $from_subcode, $from_chk,
+ $from_pid, $from_seq, $from_msg) =
+ unpack(ICMP_STRUCT . $self->{"data_size"},
+ substr($recv_msg, length($recv_msg) - $len_msg,
+ $len_msg));
+ if (($from_type == ICMP_ECHOREPLY) &&
+ (!$source_verify || $from_ip eq $ip) &&
+ ($from_pid == $self->{"pid"}) && # Does the packet check out?
+ ($from_seq == $self->{"seq"}))
+ {
+ $ret = 1; # It's a winner
+ $done = 1;
+ }
+ }
+ else # Oops, timed out
+ {
+ $done = 1;
}
- return($ret)
+ }
+ return $ret;
}
# Description: Do a checksum on the message. Basically sum all of
sub checksum
{
- my ($class,
- $msg # The message to checksum
- ) = @_;
- my ($len_msg, # Length of the message
- $num_short, # The number of short words in the message
- $short, # One short word
- $chk # The checksum
- );
-
- $len_msg = length($msg);
- $num_short = $len_msg / 2;
- $chk = 0;
- foreach $short (unpack("S$num_short", $msg))
- {
- $chk += $short;
- } # Add the odd byte in
- $chk += unpack("C", substr($msg, $len_msg - 1, 1)) if $len_msg % 2;
- $chk = ($chk >> 16) + ($chk & 0xffff); # Fold high into low
- return(~(($chk >> 16) + $chk) & 0xffff); # Again and complement
+ my ($class,
+ $msg # The message to checksum
+ ) = @_;
+ my ($len_msg, # Length of the message
+ $num_short, # The number of short words in the message
+ $short, # One short word
+ $chk # The checksum
+ );
+
+ $len_msg = length($msg);
+ $num_short = int($len_msg / 2);
+ $chk = 0;
+ foreach $short (unpack("S$num_short", $msg))
+ {
+ $chk += $short;
+ } # Add the odd byte in
+ $chk += (unpack("C", substr($msg, $len_msg - 1, 1)) << 8) if $len_msg % 2;
+ $chk = ($chk >> 16) + ($chk & 0xffff); # Fold high into low
+ return(~(($chk >> 16) + $chk) & 0xffff); # Again and complement
}
+
# Description: Perform a tcp echo ping. Since a tcp connection is
# host specific, we have to open and close each connection here. We
# can't just leave a socket open. Because of the robust nature of
# tcp, it will take a while before it gives up trying to establish a
-# connection. Therefore, we have to set the alarm to break out of the
-# connection sooner if the timeout expires. No data bytes are actually
+# connection. Therefore, we use select() on a non-blocking socket to
+# check against our timeout. No data bytes are actually
# sent since the successful establishment of a connection is proof
# enough of the reachability of the remote host. Also, tcp is
# expensive and doesn't need our help to add to the overhead.
sub ping_tcp
{
- my ($self,
- $ip, # Packed IP number of the host
- $timeout # Seconds after which ping times out
- ) = @_;
- my ($saddr, # sockaddr_in with port and ip
- $ret # The return value
- );
-
- socket($self->{"fh"}, &PF_INET(), &SOCK_STREAM(), $self->{"proto_num"}) ||
- croak("tcp socket error - $!");
- $saddr = sockaddr_in($self->{"port_num"}, $ip);
-
- $SIG{'ALRM'} = sub { die };
- alarm($timeout); # Interrupt connect() if we have to
-
- $ret = 0; # Default to unreachable
- eval <<'EOM' ;
- return unless connect($self->{"fh"}, $saddr);
- $ret = 1;
+ my ($self,
+ $ip, # Packed IP number of the host
+ $timeout # Seconds after which ping times out
+ ) = @_;
+ my ($ret # The return value
+ );
+
+ $@ = ""; $! = 0;
+ $ret = $self -> tcp_connect( $ip, $timeout);
+ if (!$self->{"tcp_econnrefused"} &&
+ $! == ECONNREFUSED) {
+ $ret = 1; # "Connection refused" means reachable
+ }
+ $self->{"fh"}->close();
+ return $ret;
+}
+
+sub tcp_connect
+{
+ my ($self,
+ $ip, # Packed IP number of the host
+ $timeout # Seconds after which connect times out
+ ) = @_;
+ my ($saddr); # Packed IP and Port
+
+ $saddr = sockaddr_in($self->{"port_num"}, $ip);
+
+ my $ret = 0; # Default to unreachable
+
+ my $do_socket = sub {
+ socket($self->{"fh"}, PF_INET, SOCK_STREAM, $self->{"proto_num"}) ||
+ croak("tcp socket error - $!");
+ if (defined $self->{"local_addr"} &&
+ !CORE::bind($self->{"fh"}, sockaddr_in(0, $self->{"local_addr"}))) {
+ croak("tcp bind error - $!");
+ }
+ if ($self->{'device'}) {
+ setsockopt($self->{"fh"}, SOL_SOCKET, SO_BINDTODEVICE(), pack("Z*", $self->{'device'}))
+ or croak("error binding to device $self->{'device'} $!");
+ }
+ };
+ 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 $!;
+ }
+ }
+
+ &{ $do_socket }();
+
+ my $patience = &time() + $timeout;
+
+ my ($child);
+ $? = 0;
+ # Wait up to the timeout
+ # And clean off the zombie
+ do {
+ $child = waitpid($pid, &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 }();
+
+ local $SIG{'ALRM'} = sub { die "Timed out!"; };
+ my $old = alarm($timeout); # Interrupt connect() if we have to
+
+ &{ $do_connect }();
+ alarm($old);
+ }
+
+ 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
- alarm(0);
- $self->{"fh"}->close();
- return($ret);
+
+ return $ret;
+}
+
+
+
+
+# Description: Perform a stream ping. If the tcp connection isn't
+# already open, it opens it. It then sends some data and waits for
+# a reply. It leaves the stream open on exit.
+
+sub ping_stream
+{
+ my ($self,
+ $ip, # Packed IP number of the host
+ $timeout # Seconds after which ping times out
+ ) = @_;
+
+ # Open the stream if it's not already open
+ if(!defined $self->{"fh"}->fileno()) {
+ $self->tcp_connect($ip, $timeout) or return 0;
+ }
+
+ croak "tried to switch servers while stream pinging"
+ if $self->{"ip"} ne $ip;
+
+ return $self->tcp_echo($timeout, $pingstring);
+}
+
+# Description: opens the stream. You would do this if you want to
+# separate the overhead of opening the stream from the first ping.
+
+sub open
+{
+ my ($self,
+ $host, # Host or IP address
+ $timeout # Seconds after which open times out
+ ) = @_;
+
+ my ($ip); # Packed IP number of the host
+ $ip = inet_aton($host);
+ $timeout = $self->{"timeout"} unless $timeout;
+
+ if($self->{"proto"} eq "stream") {
+ if(defined($self->{"fh"}->fileno())) {
+ croak("socket is already open");
+ } else {
+ $self->tcp_connect($ip, $timeout);
+ }
+ }
}
+
# Description: Perform a udp echo ping. Construct a message of
# at least the one-byte sequence number and any additional data bytes.
# Send the message out and wait for a message to come back. If we
# done. Otherwise go back and wait for the message until we run out
# of time. Return the result of our efforts.
+use constant UDP_FLAGS => 0; # Nothing special on send or recv
+
sub ping_udp
{
- my ($self,
- $ip, # Packed IP number of the host
- $timeout # Seconds after which ping times out
- ) = @_;
-
- my $flags = 0; # Nothing special on open
-
- my ($saddr, # sockaddr_in with port and ip
- $ret, # The return value
- $msg, # Message to be echoed
- $finish_time, # Time ping should be finished
- $done, # Set to 1 when we are done pinging
- $rbits, # Read bits, filehandles for reading
- $nfound, # Number of ready filehandles found
- $from_saddr, # sockaddr_in of sender
- $from_msg, # Characters echoed by $host
- $from_port, # Port message was echoed from
- $from_ip # Packed IP number of sender
- );
-
- $saddr = sockaddr_in($self->{"port_num"}, $ip);
- $self->{"seq"} = ($self->{"seq"} + 1) % 256; # Increment sequence
- $msg = chr($self->{"seq"}) . $self->{"data"}; # Add data if any
- send($self->{"fh"}, $msg, $flags, $saddr); # Send it
-
- $rbits = "";
- vec($rbits, $self->{"fh"}->fileno(), 1) = 1;
- $ret = 0; # Default to unreachable
- $done = 0;
- $finish_time = time() + $timeout; # Ping needs to be done by then
- while (!$done && $timeout > 0)
+ my ($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
+ $msg, # Message to be echoed
+ $finish_time, # Time ping should be finished
+ $done, # Set to 1 when we are done pinging
+ $rbits, # Read bits, filehandles for reading
+ $nfound, # Number of ready filehandles found
+ $from_saddr, # sockaddr_in of sender
+ $from_msg, # Characters echoed by $host
+ $from_port, # Port message was echoed from
+ $from_ip # Packed IP number of sender
+ );
+
+ $saddr = sockaddr_in($self->{"port_num"}, $ip);
+ $self->{"seq"} = ($self->{"seq"} + 1) % 256; # Increment sequence
+ $msg = chr($self->{"seq"}) . $self->{"data"}; # Add data if any
+ send($self->{"fh"}, $msg, UDP_FLAGS, $saddr); # Send it
+
+ $rbits = "";
+ vec($rbits, $self->{"fh"}->fileno(), 1) = 1;
+ $ret = 0; # Default to unreachable
+ $done = 0;
+ $finish_time = &time() + $timeout; # Ping needs to be done by then
+ while (!$done && $timeout > 0)
+ {
+ $nfound = select($rbits, undef, undef, $timeout); # Wait for response
+ $timeout = $finish_time - &time(); # Get remaining time
+
+ if (!defined($nfound)) # Hmm, a strange error
{
- $nfound = select($rbits, undef, undef, $timeout); # Wait for response
- $timeout = $finish_time - time(); # Get remaining time
+ $ret = undef;
+ $done = 1;
+ }
+ elsif ($nfound) # A packet is waiting
+ {
+ $from_msg = "";
+ $from_saddr = recv($self->{"fh"}, $from_msg, 1500, UDP_FLAGS)
+ or last; # For example an unreachable host will make recv() fail.
+ ($from_port, $from_ip) = sockaddr_in($from_saddr);
+ if (!$source_verify ||
+ (($from_ip eq $ip) && # Does the packet check out?
+ ($from_port == $self->{"port_num"}) &&
+ ($from_msg eq $msg)))
+ {
+ $ret = 1; # It's a winner
+ $done = 1;
+ }
+ }
+ else # Oops, timed out
+ {
+ $done = 1;
+ }
+ }
+ return $ret;
+}
+
+# Description: Send a TCP SYN packet to host specified.
+sub ping_syn
+{
+ my $self = shift;
+ my $host = shift;
+ my $ip = shift;
+ my $start_time = shift;
+ my $stop_time = shift;
+
+ if ($syn_forking) {
+ return $self->ping_syn_fork($host, $ip, $start_time, $stop_time);
+ }
+
+ my $fh = FileHandle->new();
+ my $saddr = sockaddr_in($self->{"port_num"}, $ip);
+
+ # Create TCP socket
+ if (!socket ($fh, PF_INET, SOCK_STREAM, $self->{"proto_num"})) {
+ croak("tcp socket error - $!");
+ }
+
+ if (defined $self->{"local_addr"} &&
+ !CORE::bind($fh, sockaddr_in(0, $self->{"local_addr"}))) {
+ croak("tcp bind error - $!");
+ }
+
+ if ($self->{'device'}) {
+ setsockopt($fh, SOL_SOCKET, SO_BINDTODEVICE(), pack("Z*", $self->{'device'}))
+ or croak("error binding to device $self->{'device'} $!");
+ }
+
+ # Set O_NONBLOCK property on filehandle
+ if (my $flags = fcntl($fh, F_GETFL, 0)) {
+ fcntl($fh, F_SETFL, $flags | O_NONBLOCK);
+ } else {
+ croak("fcntl F_GETFL: $!");
+ }
+
+ # Attempt the non-blocking connect
+ # by just sending the TCP SYN packet
+ if (connect($fh, $saddr)) {
+ # Non-blocking, yet still connected?
+ # Must have connected very quickly.
+ # Can this ever really happen?
+ }
+ else {
+ # Error occurred connecting.
+ # Hopefully the connection is just still in progress.
+ if ($! != EINPROGRESS) {
+ # If not, then it really is something bad.
+ $self->{"bad"}->{$host} = $!;
+ return undef;
+ }
+ }
+
+ my $entry = [ $host, $ip, $fh, $start_time, $stop_time ];
+ $self->{"syn"}->{$fh->fileno} = $entry;
+ if ($self->{"stop_time"} < $stop_time) {
+ $self->{"stop_time"} = $stop_time;
+ }
+ vec($self->{"wbits"}, $fh->fileno, 1) = 1;
- if (!defined($nfound)) # Hmm, a strange error
- {
- $ret = undef;
- $done = 1;
+ return 1;
+}
+
+sub ping_syn_fork {
+ my ($self, $host, $ip, $start_time, $stop_time) = @_;
+
+ # Buggy Winsock API doesn't allow nonblocking connect.
+ # Hence, if our OS is Windows, we need to create a separate
+ # process to do the blocking connect attempt.
+ my $pid = fork();
+ if (defined $pid) {
+ if ($pid) {
+ # Parent process
+ my $entry = [ $host, $ip, $pid, $start_time, $stop_time ];
+ $self->{"syn"}->{$pid} = $entry;
+ if ($self->{"stop_time"} < $stop_time) {
+ $self->{"stop_time"} = $stop_time;
+ }
+ } else {
+ # Child process
+ my $saddr = sockaddr_in($self->{"port_num"}, $ip);
+
+ # Create TCP socket
+ if (!socket ($self->{"fh"}, PF_INET, SOCK_STREAM, $self->{"proto_num"})) {
+ croak("tcp socket error - $!");
+ }
+
+ if (defined $self->{"local_addr"} &&
+ !CORE::bind($self->{"fh"}, sockaddr_in(0, $self->{"local_addr"}))) {
+ croak("tcp bind error - $!");
+ }
+
+ if ($self->{'device'}) {
+ setsockopt($self->{"fh"}, SOL_SOCKET, SO_BINDTODEVICE(), pack("Z*", $self->{'device'}))
+ or croak("error binding to device $self->{'device'} $!");
+ }
+
+ $!=0;
+ # Try to connect (could take a long time)
+ connect($self->{"fh"}, $saddr);
+ # Notify parent of connect error status
+ my $err = $!+0;
+ my $wrstr = "$$ $err";
+ # Force to 10 chars including \n
+ $wrstr .= " "x(9 - length $wrstr). "\n";
+ syswrite($self->{"fork_wr"}, $wrstr);
+ exit;
+ }
+ } else {
+ # fork() failed?
+ die "fork: $!";
+ }
+ return 1;
+}
+
+# Description: Wait for TCP ACK from host specified
+# from ping_syn above. If no host is specified, wait
+# for TCP ACK from any of the hosts in the SYN queue.
+sub ack
+{
+ my $self = shift;
+
+ if ($self->{"proto"} eq "syn") {
+ if ($syn_forking) {
+ my @answer = $self->ack_unfork(shift);
+ return wantarray ? @answer : $answer[0];
+ }
+ my $wbits = "";
+ my $stop_time = 0;
+ if (my $host = shift) {
+ # Host passed as arg
+ if (exists $self->{"bad"}->{$host}) {
+ return ();
+ }
+ my $host_fd = undef;
+ foreach my $fd (keys %{ $self->{"syn"} }) {
+ my $entry = $self->{"syn"}->{$fd};
+ if ($entry->[0] eq $host) {
+ $host_fd = $fd;
+ $stop_time = $entry->[4]
+ || croak("Corrupted SYN entry for [$host]");
+ last;
}
- elsif ($nfound) # A packet is waiting
- {
- $from_msg = "";
- $from_saddr = recv($self->{"fh"}, $from_msg, 1500, $flags);
- ($from_port, $from_ip) = sockaddr_in($from_saddr);
- if (($from_ip eq $ip) && # Does the packet check out?
- ($from_port == $self->{"port_num"}) &&
- ($from_msg eq $msg))
- {
- $ret = 1; # It's a winner
- $done = 1;
+ }
+ croak("ack called on [$host] without calling ping first!")
+ unless defined $host_fd;
+ vec($wbits, $host_fd, 1) = 1;
+ } else {
+ # No $host passed so scan all hosts
+ # Use the latest stop_time
+ $stop_time = $self->{"stop_time"};
+ # Use all the bits
+ $wbits = $self->{"wbits"};
+ }
+
+ while ($wbits !~ /^\0*$/) {
+ my $timeout = $stop_time - &time();
+ # Force a minimum of 10 ms timeout.
+ $timeout = 0.01 if $timeout <= .01;
+ if (my $nfound = select(undef, (my $wout=$wbits), undef, $timeout)) {
+ # Done waiting for one of the ACKs
+ my $fd = 0;
+ # Determine which one
+ while (length $wout &&
+ !vec($wout, $fd, 1)) {
+ $fd++;
+ }
+ if (my $entry = $self->{"syn"}->{$fd}) {
+ if (getpeername($entry->[2])) {
+ # Connection established to remote host
+ delete $self->{"syn"}->{$fd};
+ vec($self->{"wbits"}, $fd, 1) = 0;
+ return wantarray ?
+ ($entry->[0], &time() - $entry->[3], inet_ntoa($entry->[1]))
+ : $entry->[0];
+ } else {
+ # TCP ACK will never come from this host
+ # because there was an error connecting.
+
+ # Wipe it from future scanning.
+ delete $self->{"syn"}->{$fd};
+ vec($self->{"wbits"}, $fd, 1) = 0;
+ vec($wbits, $fd, 1) = 0;
+
+ # This should set $! to the correct error.
+ my $char;
+ read($entry->[2],$char,1);
+ # Store the excuse why the connection failed.
+ $self->{"bad"}->{$entry->[0]} = $!;
+ if (!$self->{"tcp_econnrefused"} &&
+ $! == ECONNREFUSED) {
+ # "Connection refused" means reachable
+ return wantarray ?
+ ($entry->[0], &time() - $entry->[3], inet_ntoa($entry->[1]))
+ : $entry->[0];
}
+ # Try another socket...
+ }
+ } else {
+ warn "Corrupted SYN entry: unknown fd [$fd] ready!";
+ vec($wbits, $fd, 1) = 0;
+ vec($self->{"wbits"}, $fd, 1) = 0;
}
- else # Oops, timed out
- {
- $done = 1;
+ } elsif (defined $nfound) {
+ # Timed out waiting for ACK
+ foreach my $fd (keys %{ $self->{"syn"} }) {
+ if (vec($wbits, $fd, 1)) {
+ my $entry = $self->{"syn"}->{$fd};
+ $self->{"bad"}->{$entry->[0]} = "Timed out";
+ vec($wbits, $fd, 1) = 0;
+ vec($self->{"wbits"}, $fd, 1) = 0;
+ delete $self->{"syn"}->{$fd};
+ }
}
+ } else {
+ # Weird error occurred with select()
+ warn("select: $!");
+ $self->{"syn"} = {};
+ $wbits = "";
+ }
}
- return($ret);
-}
+ }
+ return ();
+}
+
+sub ack_unfork {
+ my $self = shift;
+ my $stop_time = $self->{"stop_time"};
+ if (my $host = shift) {
+ # Host passed as arg
+ warn "Cannot specify host for ack on win32\n";
+ }
+
+ my $rbits = "";
+ my $timeout;
+ if (keys %{ $self->{"syn"} }) {
+ # Scan all hosts that are left
+ vec($rbits, fileno($self->{"fork_rd"}), 1) = 1;
+ $timeout = $stop_time - &time();
+ } else {
+ # No hosts left to wait for
+ $timeout = 0;
+ }
+
+ if ($timeout > 0) {
+ if (my $nfound = select((my $rout=$rbits), undef, undef, $timeout)) {
+ # Done waiting for one of the ACKs
+ if (!sysread($self->{"fork_rd"}, $_, 10)) {
+ # Socket closed, which means all children are done.
+ return ();
+ }
+ my ($pid, $how) = split;
+ if ($pid) {
+ # Flush the zombie
+ waitpid($pid, 0);
+ if (my $entry = $self->{"syn"}->{$pid}) {
+ # Connection attempt to remote host is done
+ delete $self->{"syn"}->{$pid};
+ if (!$how || # If there was no error connecting
+ (!$self->{"tcp_econnrefused"} &&
+ $how == ECONNREFUSED)) { # "Connection refused" means reachable
+ return ($entry->[0], &time() - $entry->[3], inet_ntoa($entry->[1]));
+ }
+ } else {
+ # Should never happen
+ die "Unknown ping from pid [$pid]";
+ }
+ } else {
+ die "Empty response from status socket?";
+ }
+ } elsif (defined $nfound) {
+ # Timed out waiting for ACK status
+ } else {
+ # Weird error occurred with select()
+ warn("select: $!");
+ }
+ }
+ if (my @synners = keys %{ $self->{"syn"} }) {
+ # Kill all the synners
+ kill 9, @synners;
+ foreach my $pid (@synners) {
+ # Wait for the deaths to finish
+ # Then flush off the zombie
+ waitpid($pid, 0);
+ }
+ }
+ $self->{"syn"} = {};
+ return ();
+}
+
+# Description: Tell why the ack() failed
+sub nack {
+ my $self = shift;
+ my $host = shift || croak('Usage> nack($failed_ack_host)');
+ return $self->{"bad"}->{$host} || undef;
+}
-# Description: Close the connection unless we are using the tcp
-# protocol, since it will already be closed.
+# Description: Close the connection.
sub close
{
- my ($self) = @_;
+ my ($self) = @_;
- $self->{"fh"}->close() unless $self->{"proto"} eq "tcp";
+ if ($self->{"proto"} eq "syn") {
+ delete $self->{"syn"};
+ } elsif ($self->{"proto"} eq "tcp") {
+ # The connection will already be closed
+ } else {
+ $self->{"fh"}->close();
+ }
}
Net::Ping - check a remote host for reachability
+$Id: Ping.pm,v 1.33 2002/10/19 05:02:43 rob Exp $
+
=head1 SYNOPSIS
use Net::Ping;
$p->close();
$p = Net::Ping->new("icmp");
+ $p->bind($my_addr); # Specify source interface of pings
foreach $host (@host_array)
{
print "$host is ";
$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 "$host not reachable ", scalar(localtime()), "\n"
}
undef($p);
+ # Like tcp protocol, but with many hosts
+ $p = Net::Ping->new("syn");
+ $p->{port_num} = getservbyname("http", "tcp");
+ foreach $host (@host_array) {
+ $p->ping($host);
+ }
+ while (($host,$rtt,$ip) = $p->ack) {
+ print "HOST: $host [$ip] ACKed in $rtt seconds.\n";
+ }
+
+ # High precision syntax (requires Time::HiRes)
+ $p = Net::Ping->new();
+ $p->hires();
+ ($ret, $duration, $ip) = $p->ping($host, 5.5);
+ printf("$host [ip: $ip] is alive (packet return time: %.2f ms)\n", 1000 * $duration)
+ if $ret;
+ $p->close();
+
# For backward compatibility
print "$host is alive.\n" if pingecho($host);
parameters, a variable number of hosts may be pinged multiple
times and then the connection is closed.
-You may choose one of three different protocols to use for the ping.
+You may choose one of six different protocols to use for the
+ping. The "tcp" protocol is the default. Note that a live remote host
+may still fail to be pingable by one or more of these protocols. For
+example, www.microsoft.com is generally alive but not "icmp" pingable.
+
With the "tcp" protocol the ping() method attempts to establish a
connection to the remote host's echo port. If the connection is
successfully established, the remote host is considered reachable. No
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 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.
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
reachable. Specifying the "icmp" protocol requires that the program
be run as root or that the program be setuid to root.
+If the "external" protocol is specified, the ping() method attempts to
+use the C<Net::Ping::External> module to ping the remote host.
+C<Net::Ping::External> interfaces with your system's default C<ping>
+utility to perform the ping, and generally produces relatively
+accurate results. If C<Net::Ping::External> if not installed on your
+system, specifying the "external" protocol will result in an error.
+
+If the "syn" protocol is specified, the ping() method will only
+send a TCP SYN packet to the remote host then immediately return.
+If the syn packet was sent successfully, it will return a true value,
+otherwise it will return false. NOTE: Unlike the other protocols,
+the return value does NOT determine if the remote host is alive or
+not since the full TCP three-way handshake may not have completed
+yet. The remote host is only considered reachable if it receives
+a TCP ACK within the timeout specifed. To begin waiting for the
+ACK packets, use the ack() method as explained below. Use the
+"syn" protocol instead the "tcp" protocol to determine reachability
+of multiple destinations simultaneously by sending parallel TCP
+SYN packets. It will not block while testing each remote host.
+demo/fping is provided in this distribution to demonstrate the
+"syn" protocol as an example.
+This protocol does not require any special privileges.
+
=head2 Functions
=over 4
-=item Net::Ping->new([$proto [, $def_timeout [, $bytes]]]);
+=item Net::Ping->new([$proto [, $def_timeout [, $bytes [, $device ]]]]);
Create a new ping object. All of the parameters are optional. $proto
specifies the protocol to use when doing a ping. The current choices
-are "tcp", "udp" or "icmp". The default is "udp".
+are "tcp", "udp", "icmp", "stream", "syn", or "external".
+The default is "tcp".
If a default timeout ($def_timeout) in seconds is provided, it is used
when a timeout is not given to the ping() method (below). The timeout
otherwise. The maximum number of data bytes that can be specified is
1024.
+If $device is given, this device is used to bind the source endpoint
+before sending the ping packet. I beleive this only works with
+superuser privileges and with udp and icmp protocols at this time.
+
=item $p->ping($host [, $timeout]);
Ping the remote host and wait for a response. $host can be either the
hostname or the IP number of the remote host. The optional timeout
must be greater than 0 seconds and defaults to whatever was specified
-when the ping object was created. If the hostname cannot be found or
-there is a problem with the IP number, undef is returned. Otherwise,
-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.
+when the ping object was created. Returns a success flag. If the
+hostname cannot be found or there is a problem with the IP number, the
+success flag returned will be undef. Otherwise, the success flag will
+be 1 if the host is reachable and 0 if it is not. For most practical
+purposes, undef and 0 and can be treated as the same case. In array
+context, the elapsed time as well as the string form of the ip the
+host resolved to are also returned. The elapsed time value will
+be a float, as retuned by the Time::HiRes::time() function, if hires()
+has been previously called, otherwise it is returned as an integer.
+
+=item $p->source_verify( { 0 | 1 } );
+
+Allows source endpoint verification to be enabled or disabled.
+This is useful for those remote destinations with multiples
+interfaces where the response may not originate from the same
+endpoint that the original destination endpoint was sent to.
+This only affects udp and icmp protocol pings.
+
+This is enabled by default.
+
+=item $p->tcp_service_check( { 0 | 1 } );
+
+Set whether or not the tcp connect behavior should enforce
+remote service availability as well as reachability. Normally,
+if the remote server reported ECONNREFUSED, it must have been
+reachable because of the status packet that it reported.
+With this option enabled, the full three-way tcp handshake
+must have been established successfully before it will
+claim it is reachable. NOTE: It still does nothing more
+than connect and disconnect. It does not speak any protocol
+(i.e., HTTP or FTP) to ensure the remote server is sane in
+any way. The remote server CPU could be grinding to a halt
+and unresponsive to any clients connecting, but if the kernel
+throws the ACK packet, it is considered alive anyway. To
+really determine if the server is responding well would be
+application specific and is beyond the scope of Net::Ping.
+
+This only affects "tcp" and "syn" protocols.
+
+This is disabled by default.
+
+=item $p->hires( { 0 | 1 } );
+
+Causes this module to use Time::HiRes module, allowing milliseconds
+to be returned by subsequent calls to ping().
+
+This is disabled by default.
+
+=item $p->bind($local_addr);
+
+Sets the source address from which pings will be sent. This must be
+the address of one of the interfaces on the local host. $local_addr
+may be specified as a hostname or as a text IP address such as
+"192.168.1.1".
+
+If the protocol is set to "tcp", this method may be called any
+number of times, and each call to the ping() method (below) will use
+the most recent $local_addr. If the protocol is "icmp" or "udp",
+then bind() must be called at most once per object, and (if it is
+called at all) must be called before the first call to ping() for that
+object.
+
+=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->ack( [ $host ] );
+
+When using the "syn" protocol, use this method to determine
+the reachability of the remote host. This method is meant
+to be called up to as many times as ping() was called. Each
+call returns the host (as passed to ping()) that came back
+with the TCP ACK. The order in which the hosts are returned
+may not necessarily be the same order in which they were
+SYN queued using the ping() method. If the timeout is
+reached before the TCP ACK is received, or if the remote
+host is not listening on the port attempted, then the TCP
+connection will not be established and ack() will return
+undef. In list context, the host, the ack time, and the
+dotted ip string will be returned instead of just the host.
+If the optional $host argument is specified, the return
+value will be partaining to that host only.
+This call simply does nothing if you are using any protocol
+other than syn.
+
+=item $p->nack( $failed_ack_host );
+
+The reason that host $failed_ack_host did not receive a
+valid ACK. Useful to find out why when ack( $fail_ack_host )
+returns a false value.
=item $p->close();
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 INSTALL
+
+The latest source tree is available via cvs:
+
+ cvs -z3 -q -d :pserver:anonymous@cvs.roobik.com.:/usr/local/cvsroot/freeware checkout Net-Ping
+ cd Net-Ping
+
+The tarball can be created as follows:
+
+ perl Makefile.PL ; make ; make dist
+
+The latest Net::Ping release can be found at CPAN:
+
+ $CPAN/modules/by-module/Net/
+
+1) Extract the tarball
+
+ gtar -zxvf Net-Ping-xxxx.tar.gz
+ cd Net-Ping-xxxx
+
+2) Build:
+
+ make realclean
+ perl Makefile.PL
+ make
+ make test
+
+3) Install
+
+ make install
+
+Or install it RPM Style:
+
+ rpm -ta SOURCES/Net-Ping-xxxx.tar.gz
+
+ rpm -ih RPMS/noarch/perl-Net-Ping-xxxx.rpm
+
+=head1 AUTHORS
+
+ Current maintainer:
+ bbb@cpan.org (Rob Brown)
+
+ External protocol:
+ 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)
+
+=head1 COPYRIGHT
+
+Copyright (c) 2002, Rob Brown. All rights reserved.
+
+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.
+
=cut
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