tailscale/health
Josh Bleecher Snyder 744de615f1 health, wgenegine: fix receive func health checks for the fourth time
The old implementation knew too much about how wireguard-go worked.
As a result, it missed genuine problems that occurred due to unrelated bugs.

This fourth attempt to fix the health checks takes a black box approach.
A receive func is healthy if one (or both) of these conditions holds:

* It is currently running and blocked.
* It has been executed recently.

The second condition is required because receive functions
are not continuously executing. wireguard-go calls them and then
processes their results before calling them again.

There is a theoretical false positive if wireguard-go go takes
longer than one minute to process the results of a receive func execution.
If that happens, we have other problems.

Updates #1790

Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
2021-04-26 17:35:49 -07:00
..
health.go health, wgenegine: fix receive func health checks for the fourth time 2021-04-26 17:35:49 -07:00