One of the most common "unexpected" log lines is:
"network state changed, but stringification didn't"
One way that this can occur is if an interesting interface
(non-Tailscale, has interesting IP address)
gains or loses an uninteresting IP address (link local or loopback).
The fact that the interface is interesting is enough for EqualFiltered
to inspect it. The fact that an IP address changed is enough for
EqualFiltered to declare that the interfaces are not equal.
But the State.String method reasonably declines to print any
uninteresting IP addresses. As a result, the network state appears
to have changed, but the stringification did not.
The String method is correct; nothing interesting happened.
This change fixes this by adding an IP address filter to EqualFiltered
in addition to the interface filter. This lets the network monitor
ignore the addition/removal of uninteresting IP addresses.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Google Cloud Run does not implement NETLINK_ROUTE RTMGRP.
If initialization of the netlink socket or group membership
fails, fall back to a polling implementation.
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
Not great, but lets people working on new ports get going more quickly
without having to do everything up front.
As the link monitor is getting used more, I felt bad having a useless
implementation.
Updates #815
Updates #1427
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Todd Neal
Josh Bleecher Snyder
Denton Gentry
Brad Fitzpatrick