By default all probes with the same probe interval that have been added
together will run on a synchronized schedule, which results in spiky
resource usage and potential throttling by third-party systems (for
example, OCSP servers used by the TLS probes).
To address this, prober can now run in "spread" mode that will
introduce a random delay before the first run of each probe.
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
This ensures that each DERP server is probed individually (TLS and STUN)
and also manages per-region mesh probing. Actual probing code has been
copied from cmd/derpprobe.
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
Instead of treating any interface with a non-ifscope route as a
potential default gateway, now verify that a given route is
actually a default route (0.0.0.0/0 or ::/0).
Fixes#5879
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
TLS prober now checks validity period for all server certificates
and verifies OCSP revocation status for the leaf cert.
Signed-off-by: Anton Tolchanov <anton@tailscale.com>