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libtdevnc/x11vnc/misc/ultravnc_repeater.pl

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#!/usr/bin/env perl
#
# Copyright (c) 2009-2010 by Karl J. Runge <runge@karlrunge.com>
#
# ultravnc_repeater.pl is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or (at
# your option) any later version.
#
# ultravnc_repeater.pl is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with ultravnc_repeater.pl; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA
# or see <http://www.gnu.org/licenses/>.
#
my $usage = '
ultravnc_repeater.pl:
perl script implementing the ultravnc repeater
proxy protocol.
protocol: Listen on one port for vnc clients (default 5900.)
Listen on one port for vnc servers (default 5500.)
Read 250 bytes from connecting vnc client or server.
Accept ID:<string> from clients and servers, connect them
together once both are present.
The string "RFB 000.000\n" is sent to the client (the client
must understand this means send ID:... or host:port.)
Also accept <host>:<port> from clients and make the
connection to the vnc server immediately.
Note there is no authentication or security WRT ID names or
identities; it is up to the client and server to completely
manage that aspect and whether to encrypt the session, etc.
usage: ultravnc_repeater.pl [-r] [client_port [server_port]]
Use -r to refuse new server/client connections when there is an existing
server/client ID. The default is to close the previous one.
To write to a log file set the env. var ULTRAVNC_REPEATER_LOGFILE.
To run in a loop restarting the server if it exits set the env. var.
ULTRAVNC_REPEATER_LOOP=1 or ULTRAVNC_REPEATER_LOOP=BG, the latter
forks into the background. Set ULTRAVNC_REPEATER_PIDFILE to a file
to store the master pid in.
Set ULTRAVNC_REPEATER_NO_RFB=1 to disable sending "RFB 000.000" to
the client. Then this program acts as general TCP rendezvous tool.
Examples:
ultravnc_repeater.pl
ultravnc_repeater.pl -r
ultravnc_repeater.pl 5901
ultravnc_repeater.pl 5901 5501
env ULTRAVNC_REPEATER_LOOP=BG ULTRAVNC_REPEATER_LOGFILE=/tmp/u.log ultravnc_repeater.pl ...
';
use strict;
# Set up logging:
#
if (exists $ENV{ULTRAVNC_REPEATER_LOGFILE}) {
close STDOUT;
if (!open(STDOUT, ">>$ENV{ULTRAVNC_REPEATER_LOGFILE}")) {
die "ultravnc_repeater.pl: $ENV{ULTRAVNC_REPEATER_LOGFILE} $!\n";
}
close STDERR;
open(STDERR, ">&STDOUT");
}
select(STDERR); $| = 1;
select(STDOUT); $| = 1;
# interrupt handler:
#
my $looppid = '';
my $pidfile = '';
#
sub get_out {
lprint("$_[0]:\t$$ looppid=$looppid");
if ($looppid) {
kill 'TERM', $looppid;
fsleep(0.2);
}
unlink $pidfile if $pidfile;
cleanup();
exit 0;
}
sub lprint {
print STDERR scalar(localtime), ": ", @_, "\n";
}
# These are overridden in actual server thread:
#
$SIG{INT} = \&get_out;
$SIG{TERM} = \&get_out;
# pidfile:
#
sub open_pidfile {
if (exists $ENV{ULTRAVNC_REPEATER_PIDFILE}) {
my $pf = $ENV{ULTRAVNC_REPEATER_PIDFILE};
if (open(PID, ">$pf")) {
print PID "$$\n";
close PID;
$pidfile = $pf;
} else {
lprint("could not open pidfile: $pf - $! - continuing...");
}
delete $ENV{ULTRAVNC_REPEATER_PIDFILE};
}
}
####################################################################
# Set ULTRAVNC_REPEATER_LOOP=1 to have this script create an outer loop
# restarting itself if it ever exits. Set ULTRAVNC_REPEATER_LOOP=BG to
# do this in the background as a daemon.
if (exists $ENV{ULTRAVNC_REPEATER_LOOP}) {
my $csl = $ENV{ULTRAVNC_REPEATER_LOOP};
if ($csl ne 'BG' && $csl ne '1') {
die "ultravnc_repeater.pl: invalid ULTRAVNC_REPEATER_LOOP.\n";
}
if ($csl eq 'BG') {
# go into bg as "daemon":
setpgrp(0, 0);
my $pid = fork();
if (! defined $pid) {
die "ultravnc_repeater.pl: $!\n";
} elsif ($pid) {
wait;
exit 0;
}
if (fork) {
exit 0;
}
setpgrp(0, 0);
close STDIN;
if (! $ENV{ULTRAVNC_REPEATER_LOGFILE}) {
close STDOUT;
close STDERR;
}
}
delete $ENV{ULTRAVNC_REPEATER_LOOP};
if (exists $ENV{ULTRAVNC_REPEATER_PIDFILE}) {
open_pidfile();
}
lprint("ultravnc_repeater.pl: starting service. master-pid=$$");
while (1) {
$looppid = fork;
if (! defined $looppid) {
sleep 10;
} elsif ($looppid) {
wait;
} else {
exec $0, @ARGV;
exit 1;
}
lprint("ultravnc_repeater.pl: re-starting service. master-pid=$$");
sleep 1;
}
exit 0;
}
if (exists $ENV{ULTRAVNC_REPEATER_PIDFILE}) {
open_pidfile();
}
# End of background/daemon stuff.
####################################################################
use warnings;
use IO::Socket::INET;
use IO::Select;
# Test for INET6 support:
#
my $have_inet6 = 0;
eval "use IO::Socket::INET6;";
$have_inet6 = 1 if $@ eq "";
print "perl module IO::Socket::INET6 not available: no IPv6 support.\n" if ! $have_inet6;
my $prog = 'ultravnc_repeater';
my %ID;
my $refuse = 0;
my $init_timeout = 5;
if (@ARGV && $ARGV[0] =~ /-h/) {
print $usage;
exit 0;
}
if (@ARGV && $ARGV[0] eq '-r') {
$refuse = 1;
lprint("enabling refuse mode (-r).");
shift;
}
my $client_port = shift;
my $server_port = shift;
$client_port = 5900 unless $client_port;
$server_port = 5500 unless $server_port;
my $uname = `uname`;
my $repeater_bufsize = 250;
$repeater_bufsize = $ENV{BUFSIZE} if exists $ENV{BUFSIZE};
my ($RIN, $WIN, $EIN, $ROUT);
my $client_listen = IO::Socket::INET->new(
Listen => 10,
LocalPort => $client_port,
ReuseAddr => 1,
Proto => "tcp"
);
my $err1 = $!;
my $err2 = '';
$client_listen = '' if ! $client_listen;
my $client_listen6 = '';
if ($have_inet6) {
eval {$client_listen6 = IO::Socket::INET6->new(
Listen => 10,
LocalPort => $client_port,
ReuseAddr => 1,
Domain => AF_INET6,
LocalAddr => "::",
Proto => "tcp"
);};
$err2 = $!;
}
if (! $client_listen && ! $client_listen6) {
cleanup();
die "$prog: error: client listen on port $client_port: $err1 - $err2\n";
}
my $server_listen = IO::Socket::INET->new(
Listen => 10,
LocalPort => $server_port,
ReuseAddr => 1,
Proto => "tcp"
);
$err1 = $!;
$err2 = '';
$server_listen = '' if ! $server_listen;
my $server_listen6 = '';
if ($have_inet6) {
eval {$server_listen6 = IO::Socket::INET6->new(
Listen => 10,
LocalPort => $server_port,
ReuseAddr => 1,
Domain => AF_INET6,
LocalAddr => "::",
Proto => "tcp"
);};
$err2 = $!;
}
if (! $server_listen && ! $server_listen6) {
cleanup();
die "$prog: error: server listen on port $server_port: $err1 - $err2\n";
}
my $select = new IO::Select();
if (! $select) {
cleanup();
die "$prog: select $!\n";
}
$select->add($client_listen) if $client_listen;
$select->add($client_listen6) if $client_listen6;
$select->add($server_listen) if $server_listen;
$select->add($server_listen6) if $server_listen6;
$SIG{INT} = sub {cleanup(); exit;};
$SIG{TERM} = sub {cleanup(); exit;};
my $SOCK1 = '';
my $SOCK2 = '';
my $CURR = '';
lprint("$prog: starting up. pid: $$");
lprint("watching for IPv4 connections on $client_port/client.") if $client_listen;
lprint("watching for IPv4 connections on $server_port/server.") if $server_listen;
lprint("watching for IPv6 connections on $client_port/client.") if $client_listen6;
lprint("watching for IPv6 connections on $server_port/server.") if $server_listen6;
my $alarm_sock = '';
my $got_alarm = 0;
sub alarm_handler {
lprint("$prog: got sig alarm.");
if ($alarm_sock ne '') {
close $alarm_sock;
}
$alarm_sock = '';
$got_alarm = 1;
}
while (my @ready = $select->can_read()) {
foreach my $fh (@ready) {
if (($client_listen && $fh == $client_listen) || ($client_listen6 && $fh == $client_listen6)) {
lprint("new vnc client connecting.");
} elsif (($server_listen && $fh == $server_listen) || ($server_listen6 && $fh == $server_listen6)) {
lprint("new vnc server connecting.");
}
my $sock = $fh->accept();
if (! $sock) {
lprint("$prog: accept $!");
next;
}
if (($client_listen && $fh == $client_listen) || ($client_listen6 && $fh == $client_listen6)) {
if (exists $ENV{ULTRAVNC_REPEATER_NO_RFB} && $ENV{ULTRAVNC_REPEATER_NO_RFB}) {
lprint("ULTRAVNC_REPEATER_NO_RFB: not sending RFB 000.000");
} else {
my $str = "RFB 000.000\n";
my $len = length $str;
my $n = syswrite($sock, $str, $len, 0);
if ($n != $len) {
lprint("$prog: bad $str write: $n != $len $!");
close $sock;
}
}
}
my $buf = '';
my $size = $repeater_bufsize;
$size = 1024 unless $size;
$SIG{ALRM} = "alarm_handler";
$alarm_sock = $sock;
$got_alarm = 0;
alarm($init_timeout);
my $n = sysread($sock, $buf, $size);
alarm(0);
if ($got_alarm) {
lprint("$prog: read timed out: $!");
} elsif (! defined $n) {
lprint("$prog: read error: $!");
} elsif ($repeater_bufsize > 0 && $n != $size) {
lprint("$prog: short read $n != $size $!");
close $sock;
} elsif (($client_listen && $fh == $client_listen) || ($client_listen6 && $fh == $client_listen6)) {
do_new_client($sock, $buf);
} elsif (($server_listen && $fh == $server_listen) || ($server_listen6 && $fh == $server_listen6)) {
do_new_server($sock, $buf);
}
}
}
sub do_new_client {
my ($sock, $buf) = @_;
if ($buf =~ /^ID:(\w+)/) {
my $id = $1;
if (exists $ID{$id} && exists $ID{$id}{client} && $ID{$id}{client} eq "0") {
if (!established($ID{$id}{sock})) {
lprint("server socket for ID:$id is no longer established, closing it.");
close $ID{$id}{sock};
delete $ID{$id};
} else {
lprint("server socket for ID:$id is still established.");
}
}
if (exists $ID{$id}) {
if ($ID{$id}{client}) {
my $ref = $refuse;
if ($ref && !established($ID{$id}{sock})) {
lprint("socket for ID:$id is no longer established, closing it.");
$ref = 0;
}
if ($ref) {
lprint("refusing extra vnc client for ID:$id.");
close $sock;
return;
} else {
lprint("closing and deleting previous vnc client with ID:$id.");
close $ID{$id}{sock};
lprint("storing new vnc client with ID:$id.");
$ID{$id}{client} = 1;
$ID{$id}{sock} = $sock;
}
} else {
lprint("hooking up new vnc client with existing vnc server for ID:$id.");
my $sock2 = $ID{$id}{sock};
delete $ID{$id};
hookup($sock, $sock2, "ID:$id");
}
} else {
lprint("storing new vnc client with ID:$id.");
$ID{$id}{client} = 1;
$ID{$id}{sock} = $sock;
}
} else {
my $str = sprintf("%s", $buf);
$str =~ s/\s*$//g;
$str =~ s/\0*$//g;
my $host = '';
my $port = '';
if ($str =~ /^(.+):(\d+)$/) {
$host = $1;
$port = $2;
} else {
$host = $str;
$port = 5900;
}
if ($port < 0) {
my $pnew = -$port;
lprint("resetting port from $port to $pnew.");
$port = $pnew;
} elsif ($port < 200) {
my $pnew = $port + 5900;
lprint("resetting port from $port to $pnew.");
$port = $pnew;
}
lprint("making vnc client connection directly to vnc server host='$host' port='$port'.");
my $sock2 = IO::Socket::INET->new(
PeerAddr => $host,
PeerPort => $port,
Proto => "tcp"
);
if (! $sock2 && $have_inet6) {
lprint("IPv4 connect error: $!, trying IPv6 ...");
eval{$sock2 = IO::Socket::INET6->new(
PeerAddr => $host,
PeerPort => $port,
Proto => "tcp"
);};
lprint("IPv6 connect error: $!") if !$sock2;
} else {
lprint("IPv4 connect error: $!") if !$sock2;
}
if (!$sock2) {
lprint("failed to connect to $host:$port.");
close $sock;
return;
}
hookup($sock, $sock2, "$host:$port");
}
}
sub do_new_server {
my ($sock, $buf) = @_;
if ($buf =~ /^ID:(\w+)/) {
my $id = $1;
my $store = 1;
if (exists $ID{$id} && exists $ID{$id}{client} && $ID{$id}{client} eq "1") {
if (!established($ID{$id}{sock})) {
lprint("client socket for ID:$id is no longer established, closing it.");
close $ID{$id}{sock};
delete $ID{$id};
} else {
lprint("client socket for ID:$id is still established.");
}
}
if (exists $ID{$id}) {
if (! $ID{$id}{client}) {
my $ref = $refuse;
if ($ref && !established($ID{$id}{sock})) {
lprint("socket for ID:$id is no longer established, closing it.");
$ref = 0;
}
if ($ref) {
lprint("refusing extra vnc server for ID:$id.");
close $sock;
return;
} else {
lprint("closing and deleting previous vnc server with ID:$id.");
close $ID{$id}{sock};
lprint("storing new vnc server with ID:$id.");
$ID{$id}{client} = 0;
$ID{$id}{sock} = $sock;
}
} else {
lprint("hooking up new vnc server with existing vnc client for ID:$id.");
my $sock2 = $ID{$id}{sock};
delete $ID{$id};
hookup($sock, $sock2, "ID:$id");
}
} else {
lprint("storing new vnc server with ID:$id.");
$ID{$id}{client} = 0;
$ID{$id}{sock} = $sock;
}
} else {
lprint("invalid ID:NNNNN string for vnc server: $buf");
close $sock;
return;
}
}
sub established {
my $fh = shift;
return established_linux_proc($fh);
# not working:
my $est = 1;
my $str = "Z";
my $res;
#$res = recv($fh, $str, 1, MSG_PEEK | MSG_DONTWAIT);
if (defined($res)) {
lprint("established OK: $! '$str'.");
$est = 1;
} else {
# would check for EAGAIN here to decide ...
lprint("established err: $! '$str'.");
$est = 1;
}
return $est;
}
sub established_linux_proc {
# hack for Linux to see if remote side has gone away:
my $fh = shift;
# if we can't figure things out, we must return true.
if ($uname !~ /Linux/) {
return 1;
}
my @proc_net_tcp = ();
if (-e "/proc/net/tcp") {
push @proc_net_tcp, "/proc/net/tcp";
}
if (-e "/proc/net/tcp6") {
push @proc_net_tcp, "/proc/net/tcp6";
}
if (! @proc_net_tcp) {
return 1;
}
my $n = fileno($fh);
if (!defined($n)) {
return 1;
}
my $proc_fd = "/proc/$$/fd/$n";
if (! -e $proc_fd) {
return 1;
}
my $val = readlink($proc_fd);
if (! defined $val || $val !~ /socket:\[(\d+)\]/) {
return 1;
}
my $num = $1;
my $st = '';
foreach my $tcp (@proc_net_tcp) {
if (! open(TCP, "<$tcp")) {
next;
}
while (<TCP>) {
next if /^\s*[A-z]/;
chomp;
# sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode
# 170: 0102000A:170C FE02000A:87FA 01 00000000:00000000 00:00000000 00000000 1001 0 423294766 1 f6fa4100 21 4 4 2 -1
# 172: 0102000A:170C FE02000A:87FA 08 00000000:00000001 00:00000000 00000000 1001 0 423294766 1 f6fa4100 21 4 4 2 -1
my @items = split(' ', $_);
my $state = $items[3];
my $inode = $items[9];
if (!defined $state || $state !~ /^\d+$/) {
next;
}
if (!defined $inode || $inode !~ /^\d+$/) {
next;
}
if ($inode == $num) {
$st = $state;
last;
}
}
close TCP;
last if $st ne '';
}
if ($st ne '' && $st != 1) {
return 0;
}
return 1;
}
sub handler {
lprint("\[$$/$CURR] got SIGTERM.");
close $SOCK1 if $SOCK1;
close $SOCK2 if $SOCK2;
exit;
}
sub hookup {
my ($sock1, $sock2, $tag) = @_;
my $worker = fork();
if (! defined $worker) {
lprint("failed to fork worker: $!");
close $sock1;
close $sock2;
return;
} elsif ($worker) {
close $sock1;
close $sock2;
wait;
} else {
cleanup();
if (fork) {
exit 0;
}
setpgrp(0, 0);
$SOCK1 = $sock1;
$SOCK2 = $sock2;
$CURR = $tag;
$SIG{TERM} = "handler";
$SIG{INT} = "handler";
xfer_both($sock1, $sock2);
exit 0;
}
}
sub xfer {
my ($in, $out) = @_;
$RIN = $WIN = $EIN = "";
$ROUT = "";
vec($RIN, fileno($in), 1) = 1;
vec($WIN, fileno($in), 1) = 1;
$EIN = $RIN | $WIN;
my $buf;
while (1) {
my $nf = 0;
while (! $nf) {
$nf = select($ROUT=$RIN, undef, undef, undef);
}
my $len = sysread($in, $buf, 8192);
if (! defined($len)) {
next if $! =~ /^Interrupted/;
lprint("\[$$/$CURR] $!");
last;
} elsif ($len == 0) {
lprint("\[$$/$CURR] Input is EOF.");
last;
}
my $offset = 0;
my $quit = 0;
while ($len) {
my $written = syswrite($out, $buf, $len, $offset);
if (! defined $written) {
lprint("\[$$/$CURR] Output is EOF. $!");
$quit = 1;
last;
}
$len -= $written;
$offset += $written;
}
last if $quit;
}
close($out);
close($in);
lprint("\[$$/$CURR] finished xfer.");
}
sub xfer_both {
my ($sock1, $sock2) = @_;
my $parent = $$;
my $child = fork();
if (! defined $child) {
lprint("$prog\[$$/$CURR] failed to fork: $!");
return;
}
$SIG{TERM} = "handler";
$SIG{INT} = "handler";
if ($child) {
lprint("[$$/$CURR] parent 1 -> 2.");
xfer($sock1, $sock2);
select(undef, undef, undef, 0.25);
if (kill 0, $child) {
select(undef, undef, undef, 0.9);
if (kill 0, $child) {
lprint("\[$$/$CURR] kill TERM child $child");
kill "TERM", $child;
} else {
lprint("\[$$/$CURR] child $child gone.");
}
}
} else {
select(undef, undef, undef, 0.05);
lprint("[$$/$CURR] child 2 -> 1.");
xfer($sock2, $sock1);
select(undef, undef, undef, 0.25);
if (kill 0, $parent) {
select(undef, undef, undef, 0.8);
if (kill 0, $parent) {
lprint("\[$$/$CURR] kill TERM parent $parent.");
kill "TERM", $parent;
} else {
lprint("\[$$/$CURR] parent $parent gone.");
}
}
}
}
sub cleanup {
close $client_listen if $client_listen;
close $client_listen6 if $client_listen6;
close $server_listen if $server_listen;
close $server_listen6 if $server_listen6;
foreach my $id (keys %ID) {
close $ID{$id}{sock};
}
}
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