Available on GNOME Shell Extensions
Icon Ping - visual ping to 8.8.8.8, based on antirez/iconping for macOS:
Many times I end using a computer in places with a poor or erratic wifi connection, so while I'm surfing the web, checking my email, or writing a message on Twitter, if something does not work as expected I'm not sure if the problem is my internet connection or a specific web site.
My reaction when this happens is to open the Terminal application in OSX and check with a ping 8.8.8.8 command if everything is working well at least at the basic level, that is, I'm able to reach internet at all?
For all this reasons I spent a few hours creating this small OSX menubar application that continuously pings the 8.8.8.8 address checking if the connection is working, and changing the menubar icon accordingly.
(Quote from http://antirez.com/iconping/)
The code is mostly a copy of Ping-indicator by trifonovkv (me developing the extension)