K 10
svn:author
V 8
melifaro
K 8
svn:date
V 27
2020-06-01T21:52:24.928685Z
K 7
svn:log
V 820
Add rib subscription API.

Currently there is no easy way of subscribing for the routing table changes.
The only existing way is to set ifa_rtrequest callback in the each protocol
 ifaddr, which is not convenient or extandable.

This change provides generic notification subscription mechanism, that will
 replace current ifa_rtrequest one and allow other applications such as
 accelerated routing lookup modules subscribe for the changes.

In particular, this change provides 2 hooks: 1) synchronous one
 (RIB_NOTIFY_IMMEDIATE), called under RIB_WLOCK, which ensures exact
 ordering of the changes and 2) async one, (RIB_NOTIFY_DELAYED)
 that is called after the change w/o holding locks. The latter one does not
 provide any notification ordering guarantee.

Differential Revision:  https://reviews.freebsd.org/D25070

END