package Net::Ping;
-# Authors: karrer@bernina.ethz.ch (Andreas Karrer)
-# pmarquess@bfsec.bt.co.uk (Paul Marquess)
-
+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 $syn_forking);
+use Fcntl qw( F_GETFL F_SETFL O_NONBLOCK );
+use Socket qw( SOCK_DGRAM SOCK_STREAM SOCK_RAW PF_INET SOL_SOCKET SO_ERROR
+ inet_aton inet_ntoa sockaddr_in );
+use POSIX qw( ENOTCONN ECONNREFUSED ECONNRESET EINPROGRESS EWOULDBLOCK EAGAIN WNOHANG );
+use FileHandle;
+use Carp;
+
@ISA = qw(Exporter);
-@EXPORT = qw(ping pingecho);
+@EXPORT = qw(pingecho);
+$VERSION = "2.31_04";
+
+sub SOL_IP { 0; };
+sub IP_TOS { 1; };
+
+# Constants
-use Socket;
-use Carp ;
+$def_timeout = 5; # Default timeout to wait for a reply
+$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
+$syn_forking = 0;
-$tcp_proto = (getprotobyname('tcp'))[2];
-$echo_port = (getservbyname('echo', 'tcp'))[2];
+if ($^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?
+ *ENOTCONN = sub() {10057;};
+ *ECONNRESET = sub() {10054;};
+ *EINPROGRESS = sub() {10036;};
+ *EWOULDBLOCK = sub() {10035;};
+# $syn_forking = 1; # XXX possibly useful in < Win2K ?
+};
-sub ping {
- croak "ping not implemented yet. Use pingecho()";
+# h2ph "asm/socket.h"
+# require "asm/socket.ph";
+sub SO_BINDTODEVICE {25;}
+
+# Description: The pingecho() subroutine is provided for backward
+# compatibility with the original Net::Ping. It accepts a host
+# name/IP and an optional timeout in seconds. Create a tcp ping
+# object and try pinging the host. The result of the ping is returned.
+
+sub pingecho
+{
+ my ($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 pingecho {
+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
+ $min_datasize # Minimum data bytes required
+ );
- croak "usage: pingecho host [timeout]"
- unless @_ == 1 || @_ == 2 ;
+ bless($self, $class);
- local ($host, $timeout) = @_;
- local (*PINGSOCK);
- local ($saddr, $ip);
- local ($ret) ;
+ $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;
- # check if $host is alive by connecting to its echo port, within $timeout
- # (default 5) seconds. returns 1 if OK, 0 if no answer, 0 if host not found
+ $timeout = $def_timeout unless $timeout; # Determine the timeout
+ croak("Default timeout for ping must be greater than 0 seconds")
+ if $timeout <= 0;
+ $self->{"timeout"} = $timeout;
- $timeout = 5 unless $timeout;
+ $self->{"device"} = $device;
- if ($host =~ /^\s*((\d+\.){3}\d+)\s*$/)
- { $ip = pack ('C4', split (/\./, $1)) }
- else
- { $ip = (gethostbyname($host))[4] }
+ $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");
- return 0 unless $ip; # "no such host"
+ $ip = inet_aton($local_addr);
+ croak("nonexistent local address $local_addr") unless defined($ip);
+ $self->{"local_addr"} = $ip; # Only used if proto is tcp
- $saddr = pack('S n a4 x8', AF_INET, $echo_port, $ip);
- $SIG{'ALRM'} = sub { die } ;
- alarm($timeout);
+ 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()");
+ }
- $ret = eval <<'EOM' ;
+ 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.
- return 0
- unless socket(PINGSOCK, PF_INET, SOCK_STREAM, $tcp_proto) ;
+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.
- return 0
- unless connect(PINGSOCK, $saddr) ;
+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;
+}
- return 1 ;
+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?
+ ($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
- alarm(0);
- close(PINGSOCK);
- $ret == 1 ? 1 : 0 ;
-}
+ 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();
+ }
+}
+
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
+ $p->{port_num} = getservbyname("http", "tcp");
+ while ($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_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);
+
+=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. $p is
+local to a subroutine and you leave the subroutine).
+
+=item pingecho($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
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