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newspup_event now detects cable plug/unplug
I have reported recent work with the minibase network utilities:
http://bkhome.org/news/201902/basic-ethernet-setup-with-minibase.html
The 'ifmon' daemon detects "aliveness" of an ethernet interface. That
is, if a cable is plugged-in, with a router or something at the other
end, that is working, then there is a "carrier" on the cable. It doesn't
mean that we have Internet connection or whatever, it just shows that
the cable is connected and functioning.
The carrier would go down if the router is turned off, back up if
turned on -- however, we observed the carrier going up and down a few
times, over about 30 seconds, before staying up, which does complicate
how we will respond to this information. Discussion here:
https://github.com/arsv/minibase/issues/8
Putting aside minibase for awhile, being able to detect cable
plug/unplug and router on/off, is very important to have as a basic
feature in EasyOS, so that the network connection can be dynamically
brought up/down in response. Rather than the current situation, where
the ethernet connection is expected to be active at bootup, and there is
no dynamic response afterward.
The utility 'pup_event_frontend_d' is launched at bootup and detects various conditions, such as whether X is up, whether there is a Internet connection. This is part of 'pup_event', described here:
http://bkhome.org/docs/pup_event/pup_event-service-management.htm
'pup_event_frontend-d' is written in BaCon and is in the 'pup-tools' PET. I have enhanced the daemon to detect carrier up/down, and here are the latest binary packages:
These were compiled in oe-qky-src, my fork of OpenEmbedded:
The latest source for pup-tools is here;
http://distro.ibiblio.org/easyos/source/oe/pyro/pup-tools-20190215.tar.gz
'pup_event_frontend_d' uses a netlink socket to monitor events from
the kernel. Extracting a tiny part of the code, there is a seconf socket
added, to wait for 'NETLINK_ROUTE' events:
pfd2.fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)
The code that receives the messages is very simple:
IF pfd2.revents NE 0 THEN
len = recv(pfd2.fd, buf, size_buf, MSG_DONTWAIT)
IF len==-1 THEN END 4
IF netcnt EQ 0 THEN
netcnt=50
'post to ipc clients, if any...
ipc_post_func("netchg_","change")
'also, let us be proactive, call a script directly...
IF FILEEXISTS("/usr/local/pup_event/netchg") THEN
SYSTEM "/usr/local/pup_event/netchg &"
ENDIF
ENDIF
ENDIF
This posts a "netchg_" IPC message to any clients that might be waiting on it. The pup_event IPC mechanism is explained here:
http://bkhome.org/docs/pup_event/pup_event_ipc.htm
Not only does this daemon detect cable carrier up/down, it also
detects a USB wifi dongle plugged/unplugged. The 'netcnt' variable is to
take care of the rapid carrier up/down that occurs when the router is
turned on -- there is an IPC generated on the first change, and any
changes over the next 50 seconds are ignored.
I have not yet written a client daemon. Will probably name it
something like 'netchgd' and it will start at bootup and await "netchg_"
IPC messages. It will then examine /sys to determine exactly what has
changed,
Tags: easy