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Date: Mon, 7 Jul 1997 15:13:56 -0700 (PDT)
From: "Eric J. Schwertfeger" <ejs@bfd.com>
To: Kenneth Ingham <ingham@i-pi.com>
cc: Nathan Dorfman <nathan@deimos.senate.org>, freebsd-questions@FreeBSD.ORG
Subject: Re: pppd Auto-reconnect?
In-Reply-To: <199707072125.PAA17502@socrates.i-pi.com>
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On Mon, 7 Jul 1997, Kenneth Ingham wrote:

> > Is it possible to have pppd reconnect automatically? I have a script
> Here's how I do mine.  I have a 24x7 dial-up PPP connection.
> 
> In /etc/ttys:
> 
> cuaa1   "/usr/sbin/pppd /dev/cuaa1 115200 -detach" unknown on insecure
> 
> So whenever it dies, init re-spawns it.  Works well.

For some reason, that doesn't work for me, sometimes I loose the ppp
connection, but pppd doesn't exit, so I came up with the following perl
script that I use for /etc/ppp/ip-up

#!/usr/bin/perl

# pppmon.pl
# a simple script to detect when pppd goes down.  functions by watching the
# incoming packetcounts returned by netstat, pinging when there's no traffic, 
# and killing ppd when the pings don't generate traffic.  Works with perl4 or 
# perl 5

# read arguments
$ifname=$ARGV[0];
$rmtaddr=$ARGV[4];

# initialize parameters
# delay is the number of seconds between updates
# limit is the number of times a 0 packet count is returned before killing
#     pppd
$delay=10;
$limit=2;

#initialize other variables
$zerocount=0;

# get ppp pid for later kill
open(INPUT,"/var/run/$ifname.pid");
$pid=int(<INPUT>);
close(INPUT);

sub ppplog
{
  ($sec,$min,$hour,$mday,$mon,$year)=localtime(time);
  $logstr=sprintf("%2.2d/%2.2d/%2.2d %2.2d:%2.2d:%2.2d ",$mon,$mday,
                      $year%100,$hour,$min,$sec).$_[0]."\n";
  open(LOG,'>>/var/log/pppmon');
  print LOG $logstr;
  close(LOG);
}

# log starting
&ppplog('pppmon started, device='.$ifname.' , process='.$pid.', remote address='.$rmtaddr);

# open netstat
open(DATA,"netstat -n -I $ifname -w $delay|");
while($line=<DATA>)
{
  if(!kill(0,$pid))
  {
    close(DATA);
    &ppplog('pppmon exiting, lost process '.$pid);
    exit;
  }
  if($line =~ /^[\s\d]+$/)
  {
    $newcount=(split(/\s+/,$line))[1];
    if($newcount==0) {
      $zerocount++;
      if($zerocount>=$limit) {
        kill('HUP',$pid);
	close(DATA);
	&ppplog('pppmon exiting, killing process '.$pid);
	exit;
      } else {
        system('/sbin/ping -c 3 '.$rmtaddr.' >/dev/null 2>/dev/null &');
      }
    } else {
      $zerocount=0;
    }
  }
}
close(DATA);
&ppplog('pppmon exiting, lost netstat for device '.$ifname);