Thanks to Angelo for helping me solve the UDP Deadlock problem... here's the solution in cas
e it helps another... 

[BTW, Yes... thank you... I promise not to post such lengthy questions in the future...]

--udp-deadlock-solution-snip--
use strict;
use IO::Socket;
use IO::Select;

use constant MAX_MSG_LEN  =>  5000;
use constant TIMEOUT      =>  2;
use constant MAX_RETRIES  =>  5;
my $msg_in;

my $host = "runner.terramagnetoscope.net";
my $port = "5001";
my $initialmsg = "1|GEOMAGROUTER|UPROCID|22";
my $pingrsps = "4|GEOMAGROUTER|XYZCAP|22";

print "Setting Up Socket...\n";

my $sock = IO::Socket::INET-> new(Proto=>'udp',PeerPort => $port, PeerAddr=>"$host") or die $
@;

my $select = IO::Select-> new($sock);

print "Sending Initial [Helo] Msg \n";

$sock-> send($initialmsg) or die "INITIALMSG Send Failed... $!";

while (1) {
  
  
      my @ready = $select-> can_read(TIMEOUT);
      
      for my $handle (@ready) {
        
        $sock-> recv($msg_in, MAX_MSG_LEN) or die "Failed... recv(): $!\n";
        
        print "SVR: $msg_in\n";
        
        if ($msg_in =~ /^3\|/) {
            
            print "\n+++ Caught KeepAlive Ping Request From $host:$port +++  \n";
            print "\n+++ Replying with KeepAlive Response [$pingrsps]\n";
           $sock-> send($pingrsps) or die "Ping Reply Send Failed... $!";
           
          }
      }
   do_retries() unless @ready;
}

$sock-> close;

sub do_retries {
  
  print "Comms Appear To be Down... will try reseting comms...\n";
    my $xctr = 0;
    my $rslt;
    
    for (1...10) {
        $xctr++;
        $rslt = $xctr - 10 ;
        print "Comms Outage... Trying Again in $rslt seconds \n";
        sleep (1);
    }
    
    eval {$sock-> send($initialmsg) or die "INITIALMSG Send Failed... $!"; };
    
}
exit;
--end-of-solution-snip--

PS: The select is a pretty tight loop in reality that I don't really like but it solves the 
problem :> )

-BigAL
bigal@[...].com
bigal@[...].net

On Wed, 20 Feb 2008 21:21:31 -0700, "BigAl" <bigal@[...].com>  wrote:
> 
> Hi all,
> 
> I've got a challenge outside my comfort zone (UDP Sockets). 
> 
> I'm trying to implement a UDP data aggregation process model that allows
> reporting by autonomic, magnetic sensors <using less connectivity overhead>
> as some reporting magnetic sensors have a low (crappy) bandwidth capability
> (read Dial-Up or Crystal Ball Comms!).
> 
> I'm writing a UDP 'Client' that signals a UDP 'Server' when I (The Client)
> am alive and ready to ingest global, magnetic sensor data. The Challenge is,
> the UDP server requires the following connection criteria:
> 
>   1. Upon connect, I (client) send an initial "HELO Packet" in pipe
> delimited format <below> as directed by the server to announce my presence.
> 
>   2. Every 60 seconds, the 'Server' Sends an "Is Client Alive?" packet
> (IsAlive packet payload begins with ^4)... I (the client) need to respond
> with a packet beginning with ^21 (I'm still here) packet beginning with ^21.
> 
> 
> The Challenge:
> 
> I am trying to simulate network outages of up to 300 seconds <Using VMWARE
> Client for Testing as that's all I've got> as this is the MAX AVG (that I've
> calculated from various, historic... IO conn outages)... 
> 
> .... However the UDP 'Client' Below that I largely modeled from "Perl
> Cookbook => Chapt 17.4" seems to hang and it will not recover despite my
> best interpretations of the process model [$SIG{ALRM}]. I've tried wrapping
> the read using select as well but the system (OS) doesn't seem to recover. 
> 
> 
> Read("you're not catching us at our best" - Jim Kirk, Trek IV).
> 
> 
> The Potential Solution: I am trying to develop a UDP 'Client' that can
> withstand a network outage of up to 300 seconds... then re-connect by
> sending a new, initial "HELO Packet" and resuming the aggregation of many
> magsensor site data.
> 
> The current script seems to hang (infinitively) without dumping to the
> &sleep_wait sub, [time-waster].
> 
> Thanks for any insight... as I am really aggravated with this UDP thing
> (thinking about going back to TCP but realize UDP is best for low bandwidth
> clients)... This is a nano-version of the real app, way condensed due to
> complexity (and my crappy programming skills) ]
> 
> PS: I'd love to spank the "powershell" weenies in the "scripting games", but
> I've not been presented with a relevant challenge yet (provided it doesn't
> include UDP Stuff!) 
> 
> 
> --start-snip--
> use IO::Socket;
> use strict;
> 
> my ($initialmsg, $MSG, $sock, $server_host, $port, $ipaddr, $hishost,
> $MAXLEN, $PORTNO, $TIMEOUT);
> 
> $server_host = "192.168.10.77"; # cant publicly display actual IP for this
> problem, yes I realize this stinks... 
> $PORTNO = "5001";
> $MAXLEN = 1024;
> $TIMEOUT = 5;
> $initialmsg = "1|GEOMAGROUTER|datafetcher|22";
>   
> $sock = IO::Socket::INET->new(
>     
>     Proto => 'udp',
>     PeerPort => $PORTNO,
>     PeerAddr => $server_host) or die "Couldnt Create Initial Socket!! \n";
> 
>     # Send Initial HELO mesg
>     $sock->send($initialmsg) or die "INITIALMSG Send Failed... $!";
> 
>    while(1) {
>      
>             eval {
>              $SIG{ALRM} = sub { die "Alarm Called on TIMEOUT \n"};
>              alarm $TIMEOUT;
>              $sock->recv($MSG, $MAXLEN) or die "Oddball REC ERR $! \n";
>              alarm 0;
>              1;
>            } or &sleep_wait;
>             
>                 ($port, $ipaddr) = sockaddr_in($sock->peername);
>                 $hishost = gethostbyaddr($ipaddr, AF_INET);
>                 print "Server $hishost responded by sending: $MSG \n";
>    }
> 
> 
> sub sleep_wait {
>     
>      print "Comms Appear To be Down... will try reseting comms...\n";
>    
>    my $xctr;
>    my $rslt;
>    
>    for (1...10) {
>         $xctr++;
>         $rslt = $xctr - 10 ;
>         print "Comms Outage... Trying Again in $rslt seconds \n";
>         sleep (1);
>     }
> }
> --end-of-snip--
> 
> 
> 
> -BigAL
> 
> bigal@[...].net 
> bigal@[...].com 
> 
> http://www.terramagnetoscope.net {magnetic research is the way to the
> future!}
> http://www.mollensoft.com {private home of my 'serious' apps}
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>  
> 
> 
> 
> _______________________________________________
> Perl-Win32-Users mailing list
> Perl-Win32-Users@[...].com
> To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
> 
> 
	



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