wintun-go loads wintun.dll only from the application directory and
System32. The MSI puts it there, but a plain "go build" tailscaled.exe run
from a terminal has no wintun.dll, and tstunNewWithWindowsRetries then
retried tstun.New for five minutes with nothing in the log but
tstunNew: backoff: 13 msec
tstunNew: backoff: 32 msec
because backoff.BackOff never logs the error it's given, and after the
timeout the function returned context.DeadlineExceeded, discarding the
real error.
Instead, log with helpful text if we detect that.
Updates #21290
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I09dca3317974a977deb9956657a7e36e9ec8c572
Brad Fitzpatrick
1a311b7e3c