Move Net::Ping from ext/ to dist/

1 files changed, 1777 insertions, 0 deletions

diff --git a/dist/Net-Ping/lib/Net/Ping.pm b/dist/Net-Ping/lib/Net/Ping.pm
new file mode 100644
index 0000000000..e9fff93eea
--- /dev/null
+++ b/dist/Net-Ping/lib/Net/Ping.pm
@@ -0,0 +1,1777 @@
+package Net::Ping;
+
+require 5.002;
+require Exporter;
+
+use strict;
+use vars qw(@ISA @EXPORT $VERSION
+            $def_timeout $def_proto $def_factor
+            $max_datasize $pingstring $hires $source_verify $syn_forking);
+use Fcntl qw( F_GETFL F_SETFL O_NONBLOCK );
+use Socket qw( SOCK_DGRAM SOCK_STREAM SOCK_RAW PF_INET SOL_SOCKET SO_ERROR
+               inet_aton inet_ntoa sockaddr_in );
+use POSIX qw( ENOTCONN ECONNREFUSED ECONNRESET EINPROGRESS EWOULDBLOCK EAGAIN WNOHANG );
+use FileHandle;
+use Carp;
+
+@ISA = qw(Exporter);
+@EXPORT = qw(pingecho);
+$VERSION = "2.36";
+
+sub SOL_IP { 0; };
+sub IP_TOS { 1; };
+
+# Constants
+
+$def_timeout = 5;           # Default timeout to wait for a reply
+$def_proto = "tcp";         # Default protocol to use for pinging
+$def_factor = 1.2;          # Default exponential backoff rate.
+$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
+  my @pairs = (ECONNREFUSED => 10061, # "Unknown Error" Special Win32 Response?
+	       ENOTCONN     => 10057,
+	       ECONNRESET   => 10054,
+	       EINPROGRESS  => 10036,
+	       EWOULDBLOCK  => 10035,
+	  );
+  while (my $name = shift @pairs) {
+    my $value = shift @pairs;
+    # When defined, these all are non-zero
+    unless (eval $name) {
+      no strict 'refs';
+      *{$name} = defined prototype \&{$name} ? sub () {$value} : sub {$value};
+    }
+  }
+#  $syn_forking = 1;    # XXX possibly useful in < Win2K ?
+};
+
+# h2ph "asm/socket.h"
+# require "asm/socket.ph";
+sub SO_BINDTODEVICE {25;}
+
+# Description:  The pingecho() subroutine is provided for backward
+# compatibility with the original Net::Ping.  It accepts a host
+# name/IP and an optional timeout in seconds.  Create a tcp ping
+# object and try pinging the host.  The result of the ping is returned.
+
+sub pingecho
+{
+  my ($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
+}
+
+# Description:  The new() method creates a new ping object.  Optional
+# parameters may be specified for the protocol to use, the timeout in
+# seconds and the size in bytes of additional data which should be
+# included in the packet.
+#   After the optional parameters are checked, the data is constructed
+# and a socket is opened if appropriate.  The object is returned.
+
+sub new
+{
+  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
+      $tos,               # Optional ToS to set
+      ) = @_;
+  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;
+
+  $self->{"tos"} = $tos;
+
+  $min_datasize = ($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->{"retrans"} = $def_factor;           # Default exponential backoff rate
+  $self->{"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'} $!";
+    }
+    if ($self->{'tos'}) {
+      setsockopt($self->{"fh"}, SOL_IP, IP_TOS(), pack("I*", $self->{'tos'}))
+        or croak "error configuring tos to $self->{'tos'} $!";
+    }
+  }
+  elsif ($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'} $!";
+    }
+    if ($self->{'tos'}) {
+      setsockopt($self->{"fh"}, SOL_IP, IP_TOS(), pack("I*", $self->{'tos'}))
+        or croak "error configuring tos to $self->{'tos'} $!";
+    }
+  }
+  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();
+      $self->{"good"} = {};
+      $self->{"bad"} = {};
+    } 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") && ($self->{"proto"} ne "syn"))
+  {
+    croak("Unknown protocol \"$self->{proto}\" in bind()");
+  }
+
+  return 1;
+}
+
+# Description: A select() wrapper that compensates for platform
+# peculiarities.
+sub mselect
+{
+    if ($_[3] > 0 and $^O eq 'MSWin32') {
+	# On windows, select() doesn't process the message loop,
+	# but sleep() will, allowing alarm() to interrupt the latter.
+	# So we chop up the timeout into smaller pieces and interleave
+	# select() and sleep() calls.
+	my $t = $_[3];
+	my $gran = 0.5;  # polling granularity in seconds
+	my @args = @_;
+	while (1) {
+	    $gran = $t if $gran > $t;
+	    my $nfound = select($_[0], $_[1], $_[2], $gran);
+	    undef $nfound if $nfound == -1;
+	    $t -= $gran;
+	    return $nfound if $nfound or !defined($nfound) or $t <= 0;
+
+	    sleep(0);
+	    ($_[0], $_[1], $_[2]) = @args;
+	}
+    }
+    else {
+	my $nfound = select($_[0], $_[1], $_[2], $_[3]);
+	undef $nfound if $nfound == -1;
+	return $nfound;
+    }
+}
+
+# Description: Allow UDP source endpoint comparison 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 connect
+# behavior should enforce remote service
+# availability as well as reachability.
+
+sub service_check
+{
+  my $self = shift;
+  $self->{"econnrefused"} = 1 unless defined
+    ($self->{"econnrefused"} = shift());
+}
+
+sub tcp_service_check
+{
+  service_check(@_);
+}
+
+# Description: Set exponential backoff for retransmission.
+# Should be > 1 to retain exponential properties.
+# If set to 0, retransmissions are disabled.
+
+sub retrans
+{
+  my $self = shift;
+  $self->{"retrans"} = shift;
+}
+
+# Description: allows the module to use milliseconds as returned by
+# the Time::HiRes module
+
+$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: Sets or clears the O_NONBLOCK flag on a file handle.
+sub socket_blocking_mode
+{
+  my ($self,
+      $fh,              # the file handle whose flags are to be modified
+      $block) = @_;     # if true then set the blocking
+                        # mode (clear O_NONBLOCK), otherwise
+                        # set the non-blocking mode (set O_NONBLOCK)
+
+  my $flags;
+  if ($^O eq 'MSWin32' || $^O eq 'VMS') {
+      # FIONBIO enables non-blocking sockets on windows and vms.
+      # FIONBIO is (0x80000000|(4<<16)|(ord('f')<<8)|126), as per winsock.h, ioctl.h
+      my $f = 0x8004667e;
+      my $v = pack("L", $block ? 0 : 1);
+      ioctl($fh, $f, $v) or croak("ioctl failed: $!");
+      return;
+  }
+  if ($flags = fcntl($fh, F_GETFL, 0)) {
+    $flags = $block ? ($flags & ~O_NONBLOCK) : ($flags | O_NONBLOCK);
+    if (!fcntl($fh, F_SETFL, $flags)) {
+      croak("fcntl F_SETFL: $!");
+    }
+  } else {
+    croak("fcntl F_GETFL: $!");
+  }
+}
+
+# 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
+# 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
+      $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 () 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_UNREACHABLE => 3; # ICMP packet types
+use constant ICMP_ECHO        => 8;
+use constant ICMP_STRUCT      => "C2 n3 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 ($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);
+  $self->{"from_ip"} = undef;
+  $self->{"from_type"} = undef;
+  $self->{"from_subcode"} = undef;
+  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 = mselect((my $rout=$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_pid = -1;
+      $from_seq = -1;
+      $from_saddr = recv($self->{"fh"}, $recv_msg, 1500, ICMP_FLAGS);
+      ($from_port, $from_ip) = sockaddr_in($from_saddr);
+      ($from_type, $from_subcode) = unpack("C2", substr($recv_msg, 20, 2));
+      if ($from_type == ICMP_ECHOREPLY) {
+        ($from_pid, $from_seq) = unpack("n3", substr($recv_msg, 24, 4))
+          if length $recv_msg >= 28;
+      } else {
+        ($from_pid, $from_seq) = unpack("n3", substr($recv_msg, 52, 4))
+          if length $recv_msg >= 56;
+      }
+      $self->{"from_ip"} = $from_ip;
+      $self->{"from_type"} = $from_type;
+      $self->{"from_subcode"} = $from_subcode;
+      if (($from_pid == $self->{"pid"}) && # Does the packet check out?
+          (! $source_verify || (inet_ntoa($from_ip) eq inet_ntoa($ip))) &&
+          ($from_seq == $self->{"seq"})) {
+        if ($from_type == ICMP_ECHOREPLY) {
+          $ret = 1;
+	  $done = 1;
+        } elsif ($from_type == ICMP_UNREACHABLE) {
+          $done = 1;
+        }
+      }
+    } else {     # Oops, timed out
+      $done = 1;
+    }
+  }
+  return $ret;
+}
+
+sub icmp_result {
+  my ($self) = @_;
+  my $ip = $self->{"from_ip"} || "";
+  $ip = "\0\0\0\0" unless 4 == length $ip;
+  return (inet_ntoa($ip),($self->{"from_type"} || 0), ($self->{"from_subcode"} || 0));
+}
+
+# Description:  Do a checksum on the message.  Basically sum all of
+# the short words and fold the high order bits into the low order bits.
+
+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 = int($len_msg / 2);
+  $chk = 0;
+  foreach $short (unpack("n$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 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 ($ret                # The return value
+      );
+
+  $! = 0;
+  $ret = $self -> tcp_connect( $ip, $timeout);
+  if (!$self->{"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'} $!");
+    }
+    if ($self->{'tos'}) {
+      setsockopt($self->{"fh"}, SOL_IP, IP_TOS(), pack("I*", $self->{'tos'}))
+        or croak "error configuring tos to $self->{'tos'} $!";
+    }
+  };
+  my $do_connect = sub {
+    $self->{"ip"} = $ip;
+    # ECONNREFUSED is 10061 on MSWin32. If we pass it as child error through $?,
+    # we'll get (10061 & 255) = 77, so we cannot check it in the parent process.
+    return ($ret = connect($self->{"fh"}, $saddr) || ($! == ECONNREFUSED && !$self->{"econnrefused"}));
+  };
+  my $do_connect_nb = sub {
+    # Set O_NONBLOCK property on filehandle
+    $self->socket_blocking_mode($self->{"fh"}, 0);
+
+    # start the connection attempt
+    if (!connect($self->{"fh"}, $saddr)) {
+      if ($! == ECONNREFUSED) {
+        $ret = 1 unless $self->{"econnrefused"};
+      } elsif ($! != EINPROGRESS && ($^O ne 'MSWin32' || $! != EWOULDBLOCK)) {
+        # EINPROGRESS is the expected error code after a connect()
+        # on a non-blocking socket.  But if the kernel immediately
+        # determined that this connect() will never work,
+        # Simply respond with "unreachable" status.
+        # (This can occur on some platforms with errno
+        # EHOSTUNREACH or ENETUNREACH.)
+        return 0;
+      } else {
+        # Got the expected EINPROGRESS.
+        # Just wait for connection completion...
+        my ($wbits, $wout, $wexc);
+        $wout = $wexc = $wbits = "";
+        vec($wbits, $self->{"fh"}->fileno, 1) = 1;
+
+        my $nfound = mselect(undef,
+			    ($wout = $wbits),
+			    ($^O eq 'MSWin32' ? ($wexc = $wbits) : undef),
+			    $timeout);
+        warn("select: $!") unless defined $nfound;
+
+        if ($nfound && vec($wout, $self->{"fh"}->fileno, 1)) {
+          # the socket is ready for writing so the connection
+          # attempt completed. test whether the connection
+          # attempt was successful or not
+
+          if (getpeername($self->{"fh"})) {
+            # Connection established to remote host
+            $ret = 1;
+          } else {
+            # TCP ACK will never come from this host
+            # because there was an error connecting.
+
+            # This should set $! to the correct error.
+            my $char;
+            sysread($self->{"fh"},$char,1);
+            $! = ECONNREFUSED if ($! == EAGAIN && $^O =~ /cygwin/i);
+
+            $ret = 1 if (!$self->{"econnrefused"}
+                         && $! == ECONNREFUSED);
+          }
+        } else {
+          # the connection attempt timed out (or there were connect
+	  # errors on Windows)
+	  if ($^O =~ 'MSWin32') {
+	      # If the connect will fail on a non-blocking socket,
+	      # winsock reports ECONNREFUSED as an exception, and we
+	      # need to fetch the socket-level error code via getsockopt()
+	      # instead of using the thread-level error code that is in $!.
+	      if ($nfound && vec($wexc, $self->{"fh"}->fileno, 1)) {
+		  $! = unpack("i", getsockopt($self->{"fh"}, SOL_SOCKET,
+			                      SO_ERROR));
+	      }
+	  }
+        }
+      }
+    } else {
+      # Connection established to remote host
+      $ret = 1;
+    }
+
+    # Unset O_NONBLOCK property on filehandle
+    $self->socket_blocking_mode($self->{"fh"}, 1);
+    $self->{"ip"} = $ip;
+    return $ret;
+  };
+
+  if ($syn_forking) {
+    # 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.
+    # XXX Above comments are not true at least for Win2K, where
+    # nonblocking connect works.
+
+    $| = 1; # Clear buffer prior to fork to prevent duplicate flushing.
+    $self->{'tcp_chld'} = fork;
+    if (!$self->{'tcp_chld'}) {
+      if (!defined $self->{'tcp_chld'}) {
+        # Fork did not work
+        warn "Fork error: $!";
+        return 0;
+      }
+      &{ $do_socket }();
+
+      # Try a slow blocking connect() call
+      # and report the status to the parent.
+      if ( &{ $do_connect }() ) {
+        $self->{"fh"}->close();
+        # No error
+        exit 0;
+      } else {
+        # Pass the error status to the parent
+        # Make sure that $! <= 255
+        exit($! <= 255 ? $! : 255);
+      }
+    }
+
+    &{ $do_socket }();
+
+    my $patience = &time() + $timeout;
+
+    my ($child, $child_errno);
+    $? = 0; $child_errno = 0;
+    # Wait up to the timeout
+    # And clean off the zombie
+    do {
+      $child = waitpid($self->{'tcp_chld'}, &WNOHANG());
+      $child_errno = $? >> 8;
+      select(undef, undef, undef, 0.1);
+    } while &time() < $patience && $child != $self->{'tcp_chld'};
+
+    if ($child == $self->{'tcp_chld'}) {
+      if ($self->{"proto"} eq "stream") {
+        # We need the socket connected here, in parent
+        # Should be safe to connect because the child finished
+        # within the timeout
+        &{ $do_connect }();
+      }
+      # $ret cannot be set by the child process
+      $ret = !$child_errno;
+    } else {
+      # Time must have run out.
+      # Put that choking client out of its misery
+      kill "KILL", $self->{'tcp_chld'};
+      # Clean off the zombie
+      waitpid($self->{'tcp_chld'}, 0);
+      $ret = 0;
+    }
+    delete $self->{'tcp_chld'};
+    $! = $child_errno;
+  } else {
+    # Otherwise don't waste the resources to fork
+
+    &{ $do_socket }();
+
+    &{ $do_connect_nb }();
+  }
+
+  return $ret;
+}
+
+sub DESTROY {
+  my $self = shift;
+  if ($self->{'proto'} eq 'tcp' &&
+      $self->{'tcp_chld'}) {
+    # Put that choking client out of its misery
+    kill "KILL", $self->{'tcp_chld'};
+    # Clean off the zombie
+    waitpid($self->{'tcp_chld'}, 0);
+  }
+}
+
+# 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(mselect($rin, $rout, undef, ($time + $timeout) - &time())) {
+
+        if($rout && vec($rout,$self->{"fh"}->fileno(),1)) {
+          my $num = syswrite($self->{"fh"}, $wrstr, length $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;
+}
+
+
+
+
+# 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
+# get a message, make sure all of its parts match.  If they do, we are
+# 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 ($saddr,             # sockaddr_in with port and ip
+      $ret,               # The return value
+      $msg,               # Message to be echoed
+      $finish_time,       # Time ping should be finished
+      $flush,             # Whether socket needs to be disconnected
+      $connect,           # Whether socket needs to be connected
+      $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
+
+  if ($self->{"connected"}) {
+    if ($self->{"connected"} ne $saddr) {
+      # Still connected to wrong destination.
+      # Need to flush out the old one.
+      $flush = 1;
+    }
+  } else {
+    # Not connected yet.
+    # Need to connect() before send()
+    $connect = 1;
+  }
+
+  # Have to connect() and send() instead of sendto()
+  # in order to pick up on the ECONNREFUSED setting
+  # from recv() or double send() errno as utilized in
+  # the concept by rdw @ perlmonks.  See:
+  # http://perlmonks.thepen.com/42898.html
+  if ($flush) {
+    # Need to socket() again to flush the descriptor
+    # This will disconnect from the old saddr.
+    socket($self->{"fh"}, PF_INET, SOCK_DGRAM,
+           $self->{"proto_num"});
+  }
+  # Connect the socket if it isn't already connected
+  # to the right destination.
+  if ($flush || $connect) {
+    connect($self->{"fh"}, $saddr);               # Tie destination to socket
+    $self->{"connected"} = $saddr;
+  }
+  send($self->{"fh"}, $msg, UDP_FLAGS);           # Send it
+
+  $rbits = "";
+  vec($rbits, $self->{"fh"}->fileno(), 1) = 1;
+  $ret = 0;                   # Default to unreachable
+  $done = 0;
+  my $retrans = 0.01;
+  my $factor = $self->{"retrans"};
+  $finish_time = &time() + $timeout;       # Ping needs to be done by then
+  while (!$done && $timeout > 0)
+  {
+    if ($factor > 1)
+    {
+      $timeout = $retrans if $timeout > $retrans;
+      $retrans*= $factor; # Exponential backoff
+    }
+    $nfound  = mselect((my $rout=$rbits), undef, undef, $timeout); # Wait for response
+    my $why = $!;
+    $timeout = $finish_time - &time();   # Get remaining time
+
+    if (!defined($nfound))  # Hmm, a strange error
+    {
+      $ret = undef;
+      $done = 1;
+    }
+    elsif ($nfound)         # A packet is waiting
+    {
+      $from_msg = "";
+      $from_saddr = recv($self->{"fh"}, $from_msg, 1500, UDP_FLAGS);
+      if (!$from_saddr) {
+        # For example an unreachable host will make recv() fail.
+        if (!$self->{"econnrefused"} &&
+            ($! == ECONNREFUSED ||
+             $! == ECONNRESET)) {
+          # "Connection refused" means reachable
+          # Good, continue
+          $ret = 1;
+        }
+        $done = 1;
+      } else {
+        ($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;
+        }
+      }
+    }
+    elsif ($timeout <= 0)              # Oops, timed out
+    {
+      $done = 1;
+    }
+    else
+    {
+      # Send another in case the last one dropped
+      if (send($self->{"fh"}, $msg, UDP_FLAGS)) {
+        # Another send worked?  The previous udp packet
+        # must have gotten lost or is still in transit.
+        # Hopefully this new packet will arrive safely.
+      } else {
+        if (!$self->{"econnrefused"} &&
+            $! == ECONNREFUSED) {
+          # "Connection refused" means reachable
+          # Good, continue
+          $ret = 1;
+        }
+        $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'} $!");
+  }
+  if ($self->{'tos'}) {
+    setsockopt($fh, SOL_IP, IP_TOS(), pack("I*", $self->{'tos'}))
+      or croak "error configuring tos to $self->{'tos'} $!";
+  }
+  # Set O_NONBLOCK property on filehandle
+  $self->socket_blocking_mode($fh, 0);
+
+  # 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,
+    # or else it wasn't very non-blocking.
+    #warn "WARNING: Nonblocking connect connected anyway? ($^O)";
+  } else {
+    # Error occurred connecting.
+    if ($! == EINPROGRESS || ($^O eq 'MSWin32' && $! == EWOULDBLOCK)) {
+      # The connection is just still in progress.
+      # This is the expected condition.
+    } else {
+      # Just save the error and continue on.
+      # The ack() can check the status later.
+      $self->{"bad"}->{$host} = $!;
+    }
+  }
+
+  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;
+
+  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'} $!");
+      }
+      if ($self->{'tos'}) {
+        setsockopt($self->{"fh"}, SOL_IP, IP_TOS(), pack("I*", $self->{'tos'}))
+          or croak "error configuring tos to $self->{'tos'} $!";
+      }
+
+      $!=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 16 chars including \n
+      $wrstr .= " "x(15 - length $wrstr). "\n";
+      syswrite($self->{"fork_wr"}, $wrstr, length $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}) {
+        if (!$self->{"econnrefused"} &&
+            $self->{"bad"}->{ $host } &&
+            (($! = ECONNREFUSED)>0) &&
+            $self->{"bad"}->{ $host } eq "$!") {
+          # "Connection refused" means reachable
+          # Good, continue
+        } else {
+          # ECONNREFUSED means no good
+          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;
+        }
+      }
+      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*\z/) {
+      my $timeout = $stop_time - &time();
+      # Force a minimum of 10 ms timeout.
+      $timeout = 0.01 if $timeout <= 0.01;
+
+      my $winner_fd = undef;
+      my $wout = $wbits;
+      my $fd = 0;
+      # Do "bad" fds from $wbits first
+      while ($wout !~ /^\0*\z/) {
+        if (vec($wout, $fd, 1)) {
+          # Wipe it from future scanning.
+          vec($wout, $fd, 1) = 0;
+          if (my $entry = $self->{"syn"}->{$fd}) {
+            if ($self->{"bad"}->{ $entry->[0] }) {
+              $winner_fd = $fd;
+              last;
+            }
+          }
+        }
+        $fd++;
+      }
+
+      if (defined($winner_fd) or my $nfound = mselect(undef, ($wout=$wbits), undef, $timeout)) {
+        if (defined $winner_fd) {
+          $fd = $winner_fd;
+        } else {
+          # Done waiting for one of the ACKs
+          $fd = 0;
+          # Determine which one
+          while ($wout !~ /^\0*\z/ &&
+                 !vec($wout, $fd, 1)) {
+            $fd++;
+          }
+        }
+        if (my $entry = $self->{"syn"}->{$fd}) {
+          # Wipe it from future scanning.
+          delete $self->{"syn"}->{$fd};
+          vec($self->{"wbits"}, $fd, 1) = 0;
+          vec($wbits, $fd, 1) = 0;
+          if (!$self->{"econnrefused"} &&
+              $self->{"bad"}->{ $entry->[0] } &&
+              (($! = ECONNREFUSED)>0) &&
+              $self->{"bad"}->{ $entry->[0] } eq "$!") {
+            # "Connection refused" means reachable
+            # Good, continue
+          } elsif (getpeername($entry->[2])) {
+            # Connection established to remote host
+            # Good, continue
+          } else {
+            # TCP ACK will never come from this host
+            # because there was an error connecting.
+
+            # This should set $! to the correct error.
+            my $char;
+            sysread($entry->[2],$char,1);
+            # Store the excuse why the connection failed.
+            $self->{"bad"}->{$entry->[0]} = $!;
+            if (!$self->{"econnrefused"} &&
+                (($! == ECONNREFUSED) ||
+                 ($! == EAGAIN && $^O =~ /cygwin/i))) {
+              # "Connection refused" means reachable
+              # Good, continue
+            } else {
+              # No good, try the next socket...
+              next;
+            }
+          }
+          # Everything passed okay, return the answer
+          return wantarray ?
+            ($entry->[0], &time() - $entry->[3], inet_ntoa($entry->[1]))
+            : $entry->[0];
+        } else {
+          warn "Corrupted SYN entry: unknown fd [$fd] ready!";
+          vec($wbits, $fd, 1) = 0;
+          vec($self->{"wbits"}, $fd, 1) = 0;
+        }
+      } 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"} = {};
+        $wbits = "";
+      }
+    }
+  }
+  return ();
+}
+
+sub ack_unfork {
+  my ($self,$host) = @_;
+  my $stop_time = $self->{"stop_time"};
+  if ($host) {
+    # Host passed as arg
+    if (my $entry = $self->{"good"}->{$host}) {
+      delete $self->{"good"}->{$host};
+      return ($entry->[0], &time() - $entry->[3], inet_ntoa($entry->[1]));
+    }
+  }
+
+  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();
+    # Force a minimum of 10 ms timeout.
+    $timeout = 0.01 if $timeout < 0.01;
+  } else {
+    # No hosts left to wait for
+    $timeout = 0;
+  }
+
+  if ($timeout > 0) {
+    my $nfound;
+    while ( keys %{ $self->{"syn"} } and
+           $nfound = mselect((my $rout=$rbits), undef, undef, $timeout)) {
+      # Done waiting for one of the ACKs
+      if (!sysread($self->{"fork_rd"}, $_, 16)) {
+        # Socket closed, which means all children are done.
+        return ();
+      }
+      my ($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->{"econnrefused"} &&
+               $how == ECONNREFUSED)) {  # "Connection refused" means reachable
+            if ($host && $entry->[0] ne $host) {
+              # A good connection, but not the host we need.
+              # Move it from the "syn" hash to the "good" hash.
+              $self->{"good"}->{$entry->[0]} = $entry;
+              # And wait for the next winner
+              next;
+            }
+            return ($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?";
+      }
+    }
+    if (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.
+
+sub close
+{
+  my ($self) = @_;
+
+  if ($self->{"proto"} eq "syn") {
+    delete $self->{"syn"};
+  } elsif ($self->{"proto"} eq "tcp") {
+    # The connection will already be closed
+  } else {
+    $self->{"fh"}->close();
+  }
+}
+
+sub port_number {
+   my $self = shift;
+   if(@_) {
+       $self->{port_num} = shift @_;
+       $self->service_check(1);
+   }
+   return $self->{port_num};
+}
+
+
+1;
+__END__
+
+=head1 NAME
+
+Net::Ping - check a remote host for reachability
+
+=head1 SYNOPSIS
+
+    use Net::Ping;
+
+    $p = Net::Ping->new();
+    print "$host is alive.\n" if $p->ping($host);
+    $p->close();
+
+    $p = Net::Ping->new("icmp");
+    $p->bind($my_addr); # Specify source interface of pings
+    foreach $host (@host_array)
+    {
+        print "$host is ";
+        print "NOT " unless $p->ping($host, 2);
+        print "reachable.\n";
+        sleep(1);
+    }
+    $p->close();
+
+    $p = Net::Ping->new("tcp", 2);
+    # Try connecting to the www port instead of the echo port
+    $p->port_number(getservbyname("http", "tcp"));
+    while ($stop_time > time())
+    {
+        print "$host not reachable ", scalar(localtime()), "\n"
+            unless $p->ping($host);
+        sleep(300);
+    }
+    undef($p);
+
+    # Like tcp protocol, but with many hosts
+    $p = Net::Ping->new("syn");
+    $p->port_number(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);
+
+=head1 DESCRIPTION
+
+This module contains methods to test the reachability of remote
+hosts on a network.  A ping object is first created with optional
+parameters, a variable number of hosts may be pinged multiple
+times and then the connection is closed.
+
+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
+data is actually echoed.  This protocol does not require any special
+privileges but has higher overhead than the "udp" and "icmp" protocols.
+
+Specifying the "udp" protocol causes the ping() method to send a udp
+packet to the remote host's echo port.  If the echoed packet is
+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
+does.  If the echoed message is received from the remote host and
+the echoed information is correct, the remote host is considered
+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 specified.  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 [, $device [, $tos ]]]]]);
+
+Create a new ping object.  All of the parameters are optional.  $proto
+specifies the protocol to use when doing a ping.  The current choices
+are "tcp", "udp", "icmp", "stream", "syn", or "external".
+The default is "tcp".
+
+If a default timeout ($def_timeout) in seconds is provided, it is used
+when a timeout is not given to the ping() method (below).  The timeout
+must be greater than 0 and the default, if not specified, is 5 seconds.
+
+If the number of data bytes ($bytes) is given, that many data bytes
+are included in the ping packet sent to the remote host. The number of
+data bytes is ignored if the protocol is "tcp".  The minimum (and
+default) number of data bytes is 1 if the protocol is "udp" and 0
+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 believe this only works with
+superuser privileges and with udp and icmp protocols at this time.
+
+If $tos is given, this ToS is configured into the socket.
+
+=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.  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->service_check( { 0 | 1 } );
+
+Set whether or not the 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.
+For udp protocol, enabling this option demands that the
+remote server replies with the same udp data that it was sent
+as defined by the udp echo service.
+
+This affects the "udp", "tcp", and "syn" protocols.
+
+This is disabled by default.
+
+=item $p->tcp_service_check( { 0 | 1 } );
+
+Deprecated method, but does the same as service_check() method.
+
+=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 pertaining 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();
+
+Close the network connection for this ping object.  The network
+connection is also closed by "undef $p".  The network connection is
+automatically closed if the ping object goes out of scope (e.g. $p is
+local to a subroutine and you leave the subroutine).
+
+=item $p->port_number([$port_number])
+
+When called with a port number, the port number used to ping is set to
+$port_number rather than using the echo port.  It also has the effect
+of calling C<$p-E<gt>service_check(1)> causing a ping to return a successful
+response only if that specific port is accessible.  This function returns
+the value of the port that C<ping()> will connect to.
+
+=item pingecho($host [, $timeout]);
+
+To provide backward compatibility with the previous version of
+Net::Ping, a pingecho() subroutine is available with the same
+functionality as before.  pingecho() uses the tcp protocol.  The
+return values and parameters are the same as described for the ping()
+method.  This subroutine is obsolete and may be removed in a future
+version of Net::Ping.
+
+=back
+
+=head1 NOTES
+
+There will be less network overhead (and some efficiency in your
+program) if you specify either the udp or the icmp protocol.  The tcp
+protocol will generate 2.5 times or more traffic for each ping than
+either udp or icmp.  If many hosts are pinged frequently, you may wish
+to implement a small wait (e.g. 25ms or more) between each ping to
+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 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
+longer to receive an echo packet from the remote host.  If the timeout
+is set too low under these conditions, it will appear that the remote
+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.  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:
+
+  $CPAN/modules/by-module/Net/
+
+1) Extract the tarball
+
+  gtar -zxvf Net-Ping-xxxx.tar.gz
+  cd Net-Ping-xxxx
+
+2) Build:
+
+  make realclean
+  perl Makefile.PL
+  make
+  make test
+
+3) Install
+
+  make install
+
+Or install it RPM Style:
+
+  rpm -ta SOURCES/Net-Ping-xxxx.tar.gz
+
+  rpm -ih RPMS/noarch/perl-Net-Ping-xxxx.rpm
+
+=head1 BUGS
+
+For a list of known issues, visit:
+
+https://rt.cpan.org/NoAuth/Bugs.html?Dist=Net-Ping
+
+To report a new bug, visit:
+
+https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Net-Ping
+
+=head1 AUTHORS
+
+  Current maintainer:
+    bbb@cpan.org (Rob Brown)
+
+  External protocol:
+    colinm@cpan.org (Colin McMillen)
+
+  Stream protocol:
+    bronson@trestle.com (Scott Bronson)
+
+  Original pingecho():
+    karrer@bernina.ethz.ch (Andreas Karrer)
+    pmarquess@bfsec.bt.co.uk (Paul Marquess)
+
+  Original Net::Ping author:
+    mose@ns.ccsn.edu (Russell Mosemann)
+
+=head1 COPYRIGHT
+
+Copyright (c) 2002-2003, Rob Brown.  All rights reserved.
+
+Copyright (c) 2001, Colin McMillen.  All rights reserved.
+
+This program is free software; you may redistribute it and/or
+modify it under the same terms as Perl itself.
+
+$Id: Ping.pm,v 1.86 2003/06/27 21:31:07 rob Exp $
+
+=cut