Thanks to Angelo for helping me solve the UDP Deadlock problem... here's the
solution in case 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... $!"; };
}
exit;
--end-of-solution-snip--
PS: The select is a pretty tight loop in reality that I don't really like but
it solves the problem :>)
-BigAL
[EMAIL PROTECTED]
[EMAIL PROTECTED]
On Wed, 20 Feb 2008 21:21:31 -0700, "BigAl" <[EMAIL PROTECTED]> wrote:
>
>Hi all,
>
>I've got a challenge outside my comfort zone (UDP Sockets).
>
>I'm trying to implement a UDP data aggregation process model that allows
>reporting by autonomic, magnetic sensors <using less connectivity overhead>
>as some reporting magnetic sensors have a low (crappy) bandwidth capability
>(read Dial-Up or Crystal Ball Comms!).
>
>I'm writing a UDP 'Client' that signals a UDP 'Server' when I (The Client)
>am alive and ready to ingest global, magnetic sensor data. The Challenge is,
>the UDP server requires the following connection criteria:
>
> 1. Upon connect, I (client) send an initial "HELO Packet" in pipe
>delimited format <below> as directed by the server to announce my presence.
>
> 2. Every 60 seconds, the 'Server' Sends an "Is Client Alive?" packet
>(IsAlive packet payload begins with ^4)... I (the client) need to respond
>with a packet beginning with ^21 (I'm still here) packet beginning with ^21.
>
>
>The Challenge:
>
>I am trying to simulate network outages of up to 300 seconds <Using VMWARE
>Client for Testing as that's all I've got> as this is the MAX AVG (that I've
>calculated from various, historic... IO conn outages)...
>
>.... However the UDP 'Client' Below that I largely modeled from "Perl
>Cookbook => Chapt 17.4" seems to hang and it will not recover despite my
>best interpretations of the process model [$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
>
>[EMAIL PROTECTED]
>[EMAIL PROTECTED]
>
>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
>[email protected]
>To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
>
>
_______________________________________________
Perl-Win32-Users mailing list
[email protected]
To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
