If send_request() fails it would return UINT32_MAX as the next
timeout. Callers pass the returned value to update_timeout_work
without validating it. This has worked only because
update_timeout_work will not set a timeout if an existing timeout
would fire earlier, and the way the state is currently structured it
is likely there will be an existing timeout. However, if work thread
retransmission from REQUESTING failed the timer would not be
rescheduled, causing the state machine to stop.
A more clean solution, which matches the behavior of send_discover(),
is to return the timeout for the next transmission even in the case
when the send fails. The observed behavior is the same as if the
network, rather than the sender, failed to transport the request.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
2c813bc620