This patch fixes following issues.
* If IPv6 neighbor table is full, stack can not add any new
neighbors. So stale counter is introduced. Whenever neighbor
enters into STALE state, stale counter will be incremented
by one. When table is full and if stack wants to add new
neighbor, oldest neighbor in STALE state will be removed
and new neighbor will be added.
* When neighbor is in PROBE state and when it exceeds max
number of PROBEs, only neighbor with router is removed.
As per RFC 4861 Appendix C, entry can be discarded. Now
neighbor will be removed from the table.
* Reachability timer has an issue. e.g. if a first entry timer
is 10 seconds, after 3 seconds, a new entry added with
only 3 seconds. But current implementation does not check
whether remaining time of current left over timeout is more
than new entry timeout or not. In this example, when new entry
timeout is 3 seconds, left over timeout from first etnry is
still 7 seconds. If k_delayed_work_remaining_get() returns
some value then new entry time out was not considered.
Which is bad. It fixed now.
* nbr_free is used sometimes to remove the neighbor. Which does
not remove route if that particulat neighbor is route to some
other neighbor. net_ipv6_nbr_rm() should be used in such places.
* Trivial changes which does not affect functionality.
Fixes#14063
Signed-off-by: Ravi kumar Veeramally <ravikumar.veeramally@linux.intel.com>
f361859fde