Beefy Boxes and Bandwidth Generously Provided by pair Networks RobOMonk
There's more than one way to do things
 
PerlMonks  

Cable Modem Check

by Ozymandias (Hermit)
on May 30, 2000 at 07:40 UTC ( #15345=CUFP: print w/ replies, xml ) Need Help??

Nascent asked a question about a Perl code snippit that would reconnect his dial-up modem if it failed. Well, this is something similar.

I have a cable modem connection, and every couple of days or so, the modem dies. It's a SURFboard SB3100, manufactured by General Instrument, although I'm told this happens with other modems, too.

Anyway. From my router/firewall box, everything appears normal; IFCONFIG reports the connection as being up, but I can't ping anything past the modem. The only fix is to reset the modem; since this modem doesn't have a power switch, the only way to do that is to unplug it, wait 30 to 45 seconds, and plug it back in.

Being a lazy X10 geek, I soon installed an appliance module and used my X10 remote to stop and restart the modem. Then I started thinking about how nice it would be not to have to hit that button. This is the result, although it's far from complete; my first "from scratch" Perl script. My intention, once I've completed it, is to use it in a cron job every 1/2 hour or so.

#!/usr/bin/perl # # File: modemcheck.pl # Description: Tests for Internet connectivity through standard cable # modem; uses X10 to reset modem in the event of failure # # Author: Ozymandias # Email: Ozymandias29@hotmail.com # Version: .3 # Copyright : 2000 Matt Beland. All rights reserved. # License: This script is redistributable under the terms of the +GPL. # # Dependencies: Heyu X10 Control software, CM11A X10 two-way controlle +r, X10 # module for modem # # Heyu can be obtained from http://www.prado.com/~dbs/ # This script was written using version 1.28h # # Variables: # # $admin_email: Email address notifications should go to # $error_email: Errorlog email; used as "From: in notifications # $device: Heyu address of cable modem; e.g., a5 or modem # $target: IP address of test target; I recommend the network gat +eway # (of your cable service, of course.) # # # User-defined variables - THESE MUST BE CHANGED FOR THE SCRIPT TO WOR +K $admin_email = "you@/didntchangeit.com"; $error_email = "did@/you.com"; $device = "a1"; $target = "192.168.1.1"; # define commands needed $ping ="/bin/ping -c 1 "; # Ping $kill_modem = "/usr/local/bin/heyu turn $device off"; # Kill modem $start_modem = "/usr/local/bin/heyu turn $device on"; # Start modem # begin test $linecount = 0; $errortime = localtime; open (I,"$ping $target |"); # Is it down? while(<I>) { chop $_; $linecount = $linecount + 1; if($linecount == 2) { if(/unreachable/i) { # Connection down $errortime = localtime; $wait = time; # Test again in 5 minutes $wait = $wait + 300; until($go >= $wait) { $go = time; }; open (II,"$ping $target |"); while(<II>) { chop $_; if(/Unreachable/) { $error = 2; $errortime = localtime; system "$kill_modem"; $wait = time; $wait = $wait + 60; until($go >= $wait) { $go = time; }; system "$start_modem"; # send "restarted" email open(III,"|/usr/lib/sendmail -t"); print III "From: $errormail\n"; print III "To: $adminmail\n"; print III "Subject: NET CONNECTION ERROR\n\n"; print III "At $errortime the net connection was"; + print III "restarted by the errorhandler.\n"; close(III); }; # send minor glitch email open(IV,"|/usr/lib/sendmail -t"); print IV "From: $errormail\n"; print IV "To: $adminmail\n"; print IV "Subject: NET CONNECTION ER +ROR\n\n"; print IV "At $errortime there was a +minor problem.\n"; print IV "No restart was necessary.\n"; close(IV); }; close(II); }; print "Test successfully completed at $errortime\n"; }; }; close(I);
This code does work; I've tested it both for "OK" conditions and failure conditions. But there's still a lot I want to do with this:

  • Add testing to avoid infinite looping (if there's another cause for the problem)
  • Add support for other X10 backends (simple)
  • Add URL-based network support - to execute X10 commands on another system
  • Extra notification if the script can't solve the problem (most likely using X10 to flash a light)
As I said, this is my first from scratch code, so helpful comments would be appreciated.

- Ozymandias

Comment on Cable Modem Check
Download Code
RE: Cable Modem Check
by providencia (Pilgrim) on Jun 03, 2000 at 23:54 UTC
    That's good work and a good idea. I have DSL and have the
    same problem after about a day of inactivity.

    I have some of the components hooked up to some appliances.
    Being a newbie I always like to have examples
    I never thought there was a perl module for it.

    Now I know.
    I couldn't use the Firecracker software because of Win2k(roomate's 'puter, mine has been
    dead for over a year.)
    This is just another reason to love and hate perl.
    Love: So many uses on SO MANY SYSTEMS/EASY TO PORT!
    Hate: I'm going to buy MORE X10 Appliance Modules(**CHA-CHING)!!!

    Now I wish there was a module to work with my Yo!MP3 player.
      I'm almost done with the next version; been on hold for a few days while I do some work that actually pays the rent.

      Next version will support the other two popular backends; ppower and xtend. I'm not currently planning any Windows support, but it shouldn't be too hard to make the conversion, if you can find a program with the same functionality as Heyu.

      I think the easier way out, though, would be to spend a Saturday morning trolling through the garage sales in your area. My X10 box is a 386-25 running RedHat 6.2; it works fine, even running the BlueLava CGI web interface. Just make sure the system you run the X10 from is NOT addressable from the outside world; I don't think you'd like to have a script kiddie find it at 3 AM. <G>

      - Ozymandias

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: CUFP [id://15345]
Approved by root
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others chanting in the Monastery: (6)
As of 2014-04-25 02:08 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    April first is:







    Results (579 votes), past polls