This reverts commit d01a7c2bda.
It seems that the performance penalty in global ea cache is actually
very high so returning back to local attribute caches in every BGP.
Channel is now just subscribing to yet another journal announcing
digested tries from the ROA table.
Creating tries in every channel on-the-fly was too slow to handle
and it ate obnoxious amounts of memory. Instead, the tries are
constructed directly in the table and the channels are notified
with the completed tries.
The delayed export-release mechanism is used to keep the tries allocated
until routes get reloaded.
Originally, this mechanism required to check whether there's enough time to work
and then to send an event. This macro combines all the logic and goes more straightforwardly
to the _end_ of the export processing loop.
One should note that there were two cases where the export processing loop
was deferred at the _beginning_, which led to ignoring some routes on
reimports. This wasn't easily noticeable in the tests until the one-task
limit got a ceiling on 300 ms to keep reasonable latency.
In future, this and rtable's data structures should be probably merged
but it isn't a good idea to do now. The used data structure is similar
to rtable -- an array of pointers to linked lists.
Feed is lockless, as with all tables.
Full export (receiving updates) is not supported yet but we don't have
any method how to use it anyway. Gonna implement it later.
There is no real need for storing bucket attributes locally and we may
save some memory by caching the attributes in one central place.
If this becomes a contention problem, we should reduce the lock load
of the central attribute cache.
Introducing a new omnipotent internal API to just pass route updates
from whatever point wherever we want.
From now on, all the exports should be processed by RT_WALK_EXPORTS
macro, and you can also issue a separate feed-only request to just get a
feed and finish.
The exporters can now also stop and the readers must expect that to
happen and recover. Main tables don't stop, though.
This commit makes the route chains in the tables atomic. This allows not
only standard exports but also feeds and bulk exports to be processed
without ever locking the table.
Design note: the overall data structures are quite brittle. We're using
RCU read-locks to keep track about readers, and we're indicating ongoing
work on the data structures by prepending a REF_OBSOLETE sentinel node
to make every reader go waiting.
All the operations are intended to stay inside nest/rt-table.c and it
may be even best to further refactor the code to hide the routing table
internal structure inside there. Nobody shall definitely write any
routines manipulating live routes in tables from outside.
BGP route attributes have flags (Optional, Transitive) that are validated
on decode and set to valid value on export. But if such attribute is
modified by filter or set internally by BGP during import, then its flags
would be zero in local tables. That usually does not matter, as they are
not used locally and they were fixed on export, but invalid flags leaked
in BMP and MRT dumps.
Keep route attribute flags set to valid values even when set by filters
or modified by BGP.
Some [redacted] (yes, myself) had a really bad idea
to rename nest/route.h to nest/rt.h while refactoring
some data structures out of it.
This led to unnecessarily complex problems with
merging updates from v2. Reverting this change
to make my life a bit easier.
At least it needed only one find-sed command:
find -name '*.[chlY]' -type f -exec sed -i 's#nest/rt.h#nest/route.h#' '{}' +
This merge was particularly difficult. I finally resorted to delete the
symbol scope active flag altogether and replace its usage by other
means.
Also I had to update custom route attribute registration to fit
both the scope updates in v2 and the data model in v3.
When MPLS is active, received routes on MPLS-aware SAFIs (ipvX-mpls,
vpnX-mpls) are automatically labeled according to active label policy and
corresponding MPLS routes are automatically generated. Also routes sent
on MPLS-aware SAFIs announce local labels when it should be done.
