How to know when a link is established or destroyed?

["Morel Bérenger" <berenger.morel@sga-automation.com>]

[-- Attachment #1: Type: text/plain, Size: 1432 bytes --]

Hello.

I am using pppd to have network access through GPRS/3G/4G on systems I
do not have physical access to.

Since I want the system to be up almost always, I am trying to manage
my daemons through runit (daemontools), which works by keeping child
process foreground and restart it when it dies for a reason or another,
eventually logging whatever came on stdout.

I can run pppd in that way, but I have no idea about how to know if the
connection is really established or not, and on some systems manual
reboot is sometimes needed, because it seems that pppd only tries 3 or
4 times to restore connection when link is cut, and if not it just
stays alive doing nothing.

So, I think either I missed the options needed to do what I need, or
there is a tool to manage pppd that I don't know, or it is not
implemented at all.

If if is not implemented at all, is it intended? Would it be fine if I
submit a patch doing this?

Note:
I am using the 2.4.7 version from the Debian 9 (stretch) package
2.4.7-1+4 on amd64.
$ uname -a
Linux PC-dev2 4.9.0-5-amd64 #1 SMP Debian 4.9.65-3+deb9u2 (2018-01-04)
x86_64 GNU/Linux

Thanks in advance.

PS: I'm not registered to this list, so I added my mail in the CC field.

-- 
SGA Automation
27 Rue Jean-Philippe Rameau
Pôle Delta
76000 Rouen
Tel : 02 32 10 38 53
Fax : 02 32 10 11 30
www.sga-automation.com
Email : berenger.morel@sga-automation.com

[-- Attachment #2: Signature digitale OpenPGP --]
[-- Type: application/pgp-signature, Size: 488 bytes --]