tailscale: DNS breaks on NixOS system after resume

What is the issue?

If tailscale is enabled before I suspend my laptop, resolving domains hangs until I do sudo tailscale down. If I then do sudo tailscale up, everything works again.

/etc/resolv.conf looks as follows:

# Generated by resolvconf
search niedzejkob.github.beta.tailscale.net
nameserver 100.100.100.100
options edns0

Steps to reproduce

1. Configure NixOS with settings similar to:

  networking.wireless.enable = true;
  # The global useDHCP flag is deprecated, therefore explicitly set to false here.
  # Per-interface useDHCP will be mandatory in the future, so this generated config
  # replicates the default behaviour.
  networking.useDHCP = false;
  networking.interfaces.wlp3s0.useDHCP = true;
  services.tailscale.enable = true;

(full config available here, probably mostly irrelevant) 2. Set up Tailscale with sudo tailscale up 3. Verify that host github.com resolves properly 4. Suspend the machine, and then wake it up. I’ve found the issue to reproduce regardless of how long the laptop is left suspended. 5. Attempt running host github.com and see that it hangs. 6. Observe that, nevertheless, domains under niedzejkob.github.beta.tailscale.net resolve properly. 7. Run sudo tailscale down and sudo tailscale up. 8. host github.com works again.

Are there any recent changes that introduced the issue?

I installed Tailscale 😉

OS

Linux

OS version

NixOS unstable

Tailscale version

1.22.2

Bug report

BUG-691539f77b145a26bac1296772c1d69e36cb2e33f8ea3596aceb3ddeb2ac1e6c-20220322151817Z-124dbfbbe0e4b57b